A watermark is an identifying image or pattern in paper that appears as various shades of lightness/darkness when viewed by transmitted light, caused by thickness or density variations in the paper. Watermarks have been used on postage stamps and other government documents to discourage counterfeiting. There are two main ways of producing watermarks in paper. Watermarks vary in their visibility. Various aids have been developed, such as watermark fluid. A watermark is useful in the examination of paper because it can be used for dating, identifying sizes, mill trademarks and locations, determining the quality of a sheet of paper; the word is used for digital practices that share similarities with physical watermarks. In one case, overprint on computer-printed output may be used to identify output from an unlicensed trial version of a program. In another instance, identifying codes can be encoded as a digital watermark for a music, picture, or other file; the origin of the water part of a watermark can be found back when a watermark was something that only existed in paper.
At that time the watermark was created by changing the thickness of the paper and thereby creating a shadow/lightness in the watermarked paper. This was done while the paper was still wet/watery and therefore the mark created by this process is called a watermark. Watermarks were first introduced in Fabriano, Italy, in 1282. Traditionally, a watermark was made by impressing a water-coated metal stamp or dandy roll onto the paper during manufacturing; the invention of the dandy roll in 1826 by John Marshall revolutionised the watermark process and made it easier for producers to watermark their paper. The dandy roll is a light roller covered by material similar to window screen, embossed with a pattern. Faint lines are made by laid wires that run parallel to the axis of the dandy roll, the bold lines are made by chain wires that run around the circumference to secure the laid wires to the roll from the outside; because the chain wires are located on the outside of the laid wires, they have a greater influence on the impression in the pulp, hence their bolder appearance than the laid wire lines.
This embossing is transferred to the pulp fibres and reducing their thickness in that area. Because the patterned portion of the page is thinner, it transmits more light through and therefore has a lighter appearance than the surrounding paper. If these lines are distinct and parallel, and/or there is a watermark the paper is termed laid paper. If the lines appear as a mesh or are indiscernible, and/or there is no watermark it is called wove paper; this method is called line drawing watermarks. Another type of watermark is called the cylinder mould watermark, it is a shaded watermark first used in 1848 that incorporates tonal depth and creates a greyscale image. Instead of using a wire covering for the dandy roll, the shaded watermark is created by areas of relief on the roll's own surface. Once dry, the paper may be rolled again to produce a watermark of thickness but with varying density; the resulting watermark is much clearer and more detailed than those made by the Dandy Roll process, as such Cylinder Mould Watermark Paper is the preferred type of watermarked paper for banknotes, motor vehicle titles, other documents where it is an important anti-counterfeiting measure.
In philately, the watermark is a key feature of a stamp, constitutes the difference between a common and a rare stamp. Collectors who encounter two otherwise identical stamps with different watermarks consider each stamp to be a separate identifiable issue; the "classic" stamp watermark is a small crown or other national symbol, appearing either once on each stamp or a continuous pattern. Watermarks were nearly universal on stamps in the 19th and early 20th centuries, but fell out of use and are not used on modern U. S. issues. Some types of embossing, such as that used to make the "cross on oval" design on early stamps of Switzerland, resemble a watermark in that the paper is thinner, but can be distinguished by having sharper edges than is usual for a normal watermark. Stamp paper watermarks show various designs, letters and pictorial elements; the process of bringing out the stamp watermark is simple. Sometimes a watermark in stamp paper can be seen just by looking at the unprinted back side of a stamp.
More the collector must use a few basic items to get a good look at the watermark. For example, watermark fluid may be applied to the back of a stamp to temporarily reveal the watermark. Using the simple watermarking method described, it can be difficult to distinguish some watermarks. Watermarks on stamps printed in yellow and orange can be difficult to see. A few mechanical devices are used by collectors to detect watermarks on stamps such as the Morley-Bright watermark detector and the more expensive Safe Signoscope; such devices can be useful for they can be used without the application of watermark fluid and allow the collector to look at the watermark for a longer period of time to more detect the watermark. Audio watermark detection Thomas Harry Saunders Allan H. Stevenson Overprinting Overprint Buxton, B. H; the Buxton Encyclopedia of Watermarks. Tappan, N. Y.: Buxton Stamp Co. 1977 114p. Felix, Ervin J; the Stamp Collector's Guidebook of Worldwide Perforations, from 1840 to date. Racine, WI.: Whitman Publishing Co. 1966 256p.
Nova Scotia is one of Canada's three Maritime Provinces, one of the four provinces that form Atlantic Canada. Its provincial capital is Halifax. Nova Scotia is the second-smallest of Canada's ten provinces, with an area of 55,284 square kilometres, including Cape Breton and another 3,800 coastal islands; as of 2016, the population was 923,598. Nova Scotia is Canada's second-most-densely populated province, after Prince Edward Island, with 17.4 inhabitants per square kilometre. "Nova Scotia" means "New Scotland" in Latin and is the recognized English-language name for the province. In both French and Scottish Gaelic, the province is directly translated as "New Scotland". In general and Slavic languages use a direct translation of "New Scotland", while most other languages use direct transliterations of the Latin / English name; the province was first named in the 1621 Royal Charter granting to Sir William Alexander in 1632 the right to settle lands including modern Nova Scotia, Cape Breton Island, Prince Edward Island, New Brunswick and the Gaspé Peninsula.
Nova Scotia is Canada's smallest province in area after Prince Edward Island. The province's mainland is the Nova Scotia peninsula surrounded by the Atlantic Ocean, including numerous bays and estuaries. Nowhere in Nova Scotia is more than 67 km from the ocean. Cape Breton Island, a large island to the northeast of the Nova Scotia mainland, is part of the province, as is Sable Island, a small island notorious for its shipwrecks 175 km from the province's southern coast. Nova Scotia has many ancient fossil-bearing rock formations; these formations are rich on the Bay of Fundy's shores. Blue Beach near Hantsport, Joggins Fossil Cliffs, on the Bay of Fundy's shores, has yielded an abundance of Carboniferous-age fossils. Wasson's Bluff, near the town of Parrsboro, has yielded both Triassic- and Jurassic-age fossils; the province contains 5,400 lakes. Nova Scotia lies in the mid-temperate zone and, although the province is surrounded by water, the climate is closer to continental climate rather than maritime.
The winter and summer temperature extremes of the continental climate are moderated by the ocean. However, winters are cold enough to be classified as continental—still being nearer the freezing point than inland areas to the west; the Nova Scotian climate is in many ways similar to the central Baltic Sea coast in Northern Europe, only wetter and snowier. This is true in spite of Nova Scotia's being some fifteen parallels south. Areas not on the Atlantic coast experience warmer summers more typical of inland areas, winter lows a little colder. Described on the provincial vehicle licence plate as Canada's Ocean Playground, Nova Scotia is surrounded by four major bodies of water: the Gulf of Saint Lawrence to the north, the Bay of Fundy to the west, the Gulf of Maine to the southwest, Atlantic Ocean to the east; the province includes regions of the Mi'kmaq nation of Mi'kma'ki. The Mi'kmaq people inhabited Nova Scotia at the time the first European colonists arrived. In 1605, French colonists established the first permanent European settlement in the future Canada at Port Royal, founding what would become known as Acadia.
The British conquest of Acadia took place in 1710. The Treaty of Utrecht in 1713 formally recognized this and returned Cape Breton Island to the French. Present-day New Brunswick still formed a part of the French colony of Acadia. After the capture of Port Royal in 1710, Francis Nicholson announced it would be renamed Annapolis Royal in honor of Queen Anne. In 1749, the capital of Nova Scotia moved from Annapolis Royal to the newly established Halifax. In 1755 the vast majority of the French population was forcibly removed in the Expulsion of the Acadians. In 1763, most of Acadia became part of Nova Scotia. In 1769, St. John's Island became a separate colony. Nova Scotia included present-day New Brunswick until that province's establishment in 1784, after the arrival of United Empire Loyalists. In 1867, Nova Scotia became one of the four founding provinces of the Canadian Confederation; the warfare on Nova Scotian soil during the 17th and 18th centuries influenced the history of Nova Scotia. The Mi'kmaq had lived in Nova Scotia for centuries.
The French arrived in 1604, Catholic Mi'kmaq and Acadians formed the majority of the population of the colony for the next 150 years. During the first 80 years the French and Acadians lived in Nova Scotia, nine significant military clashes took place as the English and Scottish and French fought for possession of the area; these encounters happened at Port Royal, Saint John, Cap de Sable and Baleine. The Acadian Civil War took place from 1640 to 1645. Beginning with King William's War in 1688, six wars took place in Nova Scotia before the British defeated the French and made peace with the Mi'kmaq: King William's War, Queen Anne's War, Father Rale's War, King George's War, Father Le Loutre’s War The Seven Years' War called the French and Indian War The battles during these wars took place Port Royal, Saint John, Chignecto, Dartmouth and Grand-Pré. Despite the British conquest of Acadia in 1710, Nova Scotia remained occupied
A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage, who affix the stamp to the face or address-side of any item of mail—an envelope or other postal cover —that they wish to send. The item is processed by the postal system, where a postmark or cancellation mark—in modern usage indicating date and point of origin of mailing—is applied to the stamp and its left and right sides to prevent its reuse; the item is delivered to its addressee. Always featuring the name of the issuing nation, a denomination of its value, an illustration of persons, institutions, or natural realities that symbolize the nation's traditions and values, every stamp is printed on a piece of rectangular, but sometimes triangular or otherwise shaped special custom-made paper whose back is either glazed with an adhesive gum or self-adhesive; because governments issue stamps of different denominations in unequal numbers and discontinue some lines and introduce others, because of their illustrations and association with the social and political realities of the time of their issue, they are prized for their beauty and historical significance by stamp collectors whose study of their history and of mailing systems is called philately.
Because collectors buy stamps from an issuing agency with no intention to use them for postage, the revenues from such purchases and payments of postage can make them a source of net profit to that agency. Throughout modern history, numerous methods were used to indicate that postage had been paid on a mailed item, so several different men have received credit for inventing the postage stamp. William DockwraIn 1680, William Dockwra, an English merchant in London, his partner Robert Murray established the London Penny Post, a mail system that delivered letters and small parcels inside the city of London for the sum of one penny. Confirmation of paid postage was indicated by the use of a hand stamp to frank the mailed item. Though this'stamp' was applied to the letter or parcel itself, rather than to a separate piece of paper, it is considered by many historians to be the world's first postage stamp. Lovrenc KoširIn 1835, the Slovene civil servant Lovrenc Košir from Ljubljana in Austria-Hungary, suggested the use of "artificially affixed postal tax stamps" using "gepresste papieroblate", but although civil bureaucrats considered the suggestion in detail, it was not adopted.
Rowland HillIn 1836, a Member of Parliament, Robert Wallace, gave Sir Rowland Hill numerous books and documents about the postal service, which Hill described as a "half hundred weight of material". After a detailed study, on 4 January 1837 Hill submitted a pamphlet entitled Post Office Reform: Its Importance and Practicability, marked "private and confidential," and not released to the general public, to the Chancellor of the Exchequer, Thomas Spring Rice; the Chancellor summoned Hill to a meeting at which he suggested improvements and changes to be presented in a supplement, which Hill duly produced and submitted on 28 January 1837. Summoned to give evidence before the Commission for Post Office Enquiry on 13 February 1837, Hill read from the letter he wrote to the Chancellor that included a statement saying that the notation of paid postage could be created "...by using a bit of paper just large enough to bear the stamp, covered at the back with a glutinous wash...". This would become the first unambiguous description of a modern adhesive postage stamp.
Shortly afterward, Hill's revision of the booklet, dated 22 February 1837, containing some 28,000 words, incorporating the supplement given to the Chancellor and statements he made to the Commission, was published and made available to the general public. Hansard records that on 15 December 1837, Benjamin Hawes asked the Chancellor of the Exchequer "whether it was the intention of the Government to give effect to the recommendation of the Commissioners of the Post-office, contained in their ninth report relating to the reduction of the rates of postage, the issuing of penny stamps?"Hill’s ideas for postage stamps and charging paid-postage based on weight soon took hold, were adopted in many countries throughout the world. With the new policy of charging by weight, using envelopes for mailing documents became the norm. Hill’s brother Edwin invented a prototype envelope-making machine that folded paper into envelopes enough to match the pace of the growing demand for postage stamps. Rowland Hill and the reforms he introduced to the United Kingdom postal system appear on several of its commemorative stamps.
James ChalmersIn the 1881 book The Penny Postage Scheme of 1837, Scotsman Patrick Chalmers claimed that his father, James Chalmers, published an essay in August 1834 describing and advocating a postage stamp, but submitted no evidence of the essay's existence. Until he died in 1891, Patrick Chalmers campaigned to have his father recognized as the inventor of the postage stamp; the first independent evidence for Chalmers' claim is an essay, dated 8 February 1838 and received by the Post Office on 17 February 1838, in which he proposed adhesive postage stamps to the General Post Office. In this 800-word document concerning methods of indicating that postage had been paid on mail he states: "Therefore, of Mr Hill’s plan of a uniform rate of postage... I conceive that the most simple and economical mode... would be by Slips... in the hope that Mr Hill’s plan may soon be carried into operation I would sugg
A diamond jubilee is a celebration held to mark a 60th anniversary of an event related to a person. The 60-year reign of Queen Victoria, commemorated as the Diamond Jubilee of Queen Victoria was celebrated on 22 June 1897; the Diamond Jubilee of Queen Elizabeth II was celebrated across the Commonwealth of Nations throughout 2012. George III of the United Kingdom died a few months before his diamond jubilee was due in 1820. In East Asia, the diamond jubilee coincides with the traditional sixty-year sexagenary cycle, held in special importance despite not being called a "diamond jubilee." Monarchs such as the Kangxi and Qianlong emperors of China, Hirohito of emperor of Japan held celebrations for their sixtieth year of reign, as did King Bhumibol Adulyadej the King of Thailand on 10 June 2006. National governments mark their sixtieth anniversary as diamond jubilees, as did the Republic of Korea in 2005 and the People's Republic of China in 2009. In South Asia, the term is used for certain 100-week anniversaries.
For instance, in both India and Pakistan, a diamond jubilee film is one shown in cinemas for 100 weeks or more. The longest reigning monarch in history, Sobhuza II of Swaziland, celebrated his diamond jubilee in 1981, dating from when he gained direct rule. Silver jubilee Ruby jubilee Golden jubilee Sapphire jubilee Platinum jubilee Wedding anniversary#Celebration and gifts Hierarchy of precious substances
Tasmania is an island state of Australia. It is located 240 km to the south of the Australian mainland, separated by Bass Strait; the state encompasses the main island of Tasmania, the 26th-largest island in the world, the surrounding 334 islands. The state has a population of around 526,700 as of March 2018. Just over forty percent of the population resides in the Greater Hobart precinct, which forms the metropolitan area of the state capital and largest city, Hobart. Tasmania's area is 68,401 km2, of which the main island covers 64,519 km2, it is promoted as a natural state, protected areas of Tasmania cover about 42% of its land area, which includes national parks and World Heritage Sites. Tasmania was the founding place of the first environmental political party in the world; the island is believed to have been occupied by indigenous peoples for 30,000 years before British colonisation. It is thought Aboriginal Tasmanians were separated from the mainland Aboriginal groups about 10,000 years ago when the sea rose to form Bass Strait.
The Aboriginal population is estimated to have been between 3,000 and 7,000 at the time of colonisation, but was wiped out within 30 years by a combination of violent guerrilla conflict with settlers known as the "Black War", intertribal conflict, from the late 1820s, the spread of infectious diseases to which they had no immunity. The conflict, which peaked between 1825 and 1831, led to more than three years of martial law, cost the lives of 1,100 Aboriginals and settlers; the island was permanently settled by Europeans in 1803 as a penal settlement of the British Empire to prevent claims to the land by the First French Empire during the Napoleonic Wars. The island was part of the Colony of New South Wales but became a separate, self-governing colony under the name Van Diemen's Land in 1825. 75,000 convicts were sent to Van Diemen's Land before transportation ceased in 1853. In 1854 the present Constitution of Tasmania was passed, the following year the colony received permission to change its name to Tasmania.
In 1901 it became a state through the process of the Federation of Australia. The state is named after Dutch explorer Abel Tasman, who made the first reported European sighting of the island on 24 November 1642. Tasman named the island Anthony van Diemen's Land after his sponsor Anthony van Diemen, the Governor of the Dutch East Indies; the name was shortened to Van Diemen's Land by the British. It was renamed Tasmania in honour of its first European discoverer on 1 January 1856. Tasmania was sometimes referred to as "Dervon," as mentioned in the Jerilderie Letter written by the notorious Australian bushranger Ned Kelly in 1879; the colloquial expression for the state is "Tassie". Tasmania is colloquially shortened to "Tas," when used in business names and website addresses. TAS is the Australia Post abbreviation for the state; the reconstructed Palawa kani language name for Tasmania is Lutriwita. The island was adjoined to the mainland of Australia until the end of the last glacial period about 10,000 years ago.
Much of the island is composed of Jurassic dolerite intrusions through other rock types, sometimes forming large columnar joints. Tasmania has the world's largest areas of dolerite, with many distinctive mountains and cliffs formed from this rock type; the central plateau and the southeast portions of the island are dolerites. Mount Wellington above Hobart is a good example. In the southern midlands as far south as Hobart, the dolerite is underlaid by sandstone and similar sedimentary stones. In the southwest, Precambrian quartzites were formed from ancient sea sediments and form strikingly sharp ridges and ranges, such as Federation Peak or Frenchmans Cap. In the northeast and east, continental granites can be seen, such as at Freycinet, similar to coastal granites on mainland Australia. In the northwest and west, mineral-rich volcanic rock can be seen at Mount Read near Rosebery, or at Mount Lyell near Queenstown. Present in the south and northwest is limestone with caves; the quartzite and dolerite areas in the higher mountains show evidence of glaciation, much of Australia's glaciated landscape is found on the Central Plateau and the Southwest.
Cradle Mountain, another dolerite peak, for example, was a nunatak. The combination of these different rock types contributes to scenery, distinct from any other region of the world. In the far southwest corner of the state, the geology is wholly quartzite, which gives the mountains the false impression of having snow-capped peaks year round. Evidence indicates the presence of Aborigines in Tasmania about 42,000 years ago. Rising sea levels cut Tasmania off from mainland Australia about 10,000 years ago and by the time of European contact, the Aboriginal people in Tasmania had nine major nations or ethnic groups. At the time of the British occupation and colonisation in 1803, the indigenous population was estimated at between 3,000 and 10,000. Historian Lyndall Ryan's analysis of population studies led her to conclude that there were about 7,000 spread throughout the island's nine nations. J. B. Plomley and Rhys Jones, settled on a figure of 3,000 to 4,000, they engaged in fire-stick farming, hunted game including kangaroo and wallabies, caught seals, mutton-birds and fish and lived as nine separate "nations" on the island, which they knew as "Trouwunna".
The first reported sighting of Tasmania by a European was on 24 November 1642 by Dutch explorer Abel Tasman, who landed at today's Blackman Bay. More than a century in 1772, a French expedition le
Samuel Cousins was an English mezzotint engraver. Cousins was born at Exeter. In 1855 he was elected a full member of the Royal Academy, to which he gave in trust £15,000 to provide annuities for superannuated artists. One of the most important figures in the history of British engraving, he died in London, unmarried, in 1887. Cousins was preeminently the interpreter of his contemporary. During his apprenticeship to Samuel William Reynolds he engraved many of the best amongst the three hundred and sixty little mezzotints illustrating the works of Sir Joshua Reynolds which his master issued in his own name. In the finest of his numerous transcripts of Lawrence, such as Lady Acland and her Sons, Pope Pius VII and Master Lambton, the distinguishing characteristics of the engravers work and force of effect in a high key, corresponded with similar qualities in the painter. After the introduction of steel for engraving purposes about the year 1823, Cousins and his contemporaries were compelled to work on it, because the soft copper used for mezzotint plates did not yield a sufficient number of fine impressions to enable the method to compete commercially against line engraving, from which much larger editions were obtainable.
The painterly quality which distinguished the 18th-century mezzotints on copper was wanting in his works, because the hardness of the steel on which they were engraved impaired freedom of execution and richness of tone, so enhanced the labor of scraping that he accelerated the work by stipple, etching the details instead of scraping them out of the ground in the manner of his predecessors. To this mixed style used by Richard Earlom on copper, Cousins added heavy roulette and rocking-tool textures, tending to fortify the darks, when he found that the burr on steel failed to yield enough fine impressions to meet high demand; the effect of his prints in this method after Reynolds and Millais was mechanical and out of harmony with the picturesque technique of these painters, but the phenomenal popularity which Cousins gained for his works at least kept alive and in favor a form of mezzotint engraving during a critical phase of its history. Abraham Raimbach, the line engraver, dated the decline of his own art in England from the appearance in 1837 of Cousins's print after Landseer's Bolton Abbey.
Such plates as Miss Peel, after Lawrence. It reached its final development in the plates after Millais's Cherry Ripe and Pomona, published in 1881 and 1882, when the invention of facing copper-plates with a film of steel to make them yield larger editions led to the revival of pure mezzotint on copper, which rendered obsolete the steel plate and the mixed style which it fostered; the fine draughtsmanship of Cousins was as apparent in his prints as in his original lead-pencil portraits exhibited in London in 1882. George Pycroft, M. R. C. S. E. Memoir of Samuel Cousins, R. A. Member of the Legion of Honor. Prints & People: A Social History of Printed Pictures, an exhibition catalog from The Metropolitan Museum of Art, which contains material on Samuel Cousins Alfred Whitman. Samuel Cousins. Illustrated, from Internet Archive Profile on Royal Academy of Arts CollectionsAttribution This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Cousins, Samuel". Encyclopædia Britannica.
7. Cambridge University Press. Pp. 335–336. This article incorporates text from a publication now in the public domain: Wood, James, ed.. "Cousins, Samuel". The Nuttall Encyclopædia. London and New York: Frederick Warne
Conch is a common name applied to a number of different medium to large-sized shells. The term applies to large snails whose shell has a high spire and a noticeable siphonal canal. In North America, a conch is identified as a queen conch, indigenous to the waters of the Bahamas. Queen conchs are valued for seafood, are used as fish bait; the group of conchs that are sometimes referred to as "true conchs" are marine gastropod molluscs in the family Strombidae in the genus Strombus and other related genera. For example, see Lobatus gigas, the queen conch, Laevistrombus canarium, the dog conch. Many other species are often called "conch", but are not at all related to the family Strombidae, including Melongena species, the horse conch Triplofusus papillosus. Species referred to as conchs include the sacred chank or more shankha shell and other Turbinella species in the family Turbinellidae; the English word "conch" is attested in Middle English, coming from Latin concha, which in turn comes from Greek konchē from Proto-Indo-European root *konkho-, cognate with Sanskrit śaṅkha.
The meat of conchs is eaten raw in salads, or cooked, as in burgers, chowders and gumbos. All parts of the conch meat are edible. Conch is most indigenous to the Bahamas, is served in fritter and soup forms. Conch is eaten in the West Indies. Restaurants all over the islands serve this particular meat. In the Dominican Republic and Haiti, conch is eaten in curries or in a spicy soup, it is locally referred to as lambi. In the Turks and Caicos Islands, the Annual Conch Festival is held in November each year, located at the Three Queens Bar/Restaurant in Blue Hills. Local restaurateurs compete for the best and most original conch dishes, which are judged by international chefs. Free sampling of the dishes follows the judging. In Puerto Rico, conch is served as a ceviche called ensalada de carrucho, consisting of raw conch marinated in lime juice, olive oil, garlic, green peppers, onions, it is used to fill empanadas. In Panama, conch is known as cambombia and is served as ceviche de cambombia consisting of raw conch marinated in lime juice, chopped onions, finely chopped habaneros, vinegar.
Conch is popular in Italy and among Italian Americans. Called scungille, it is eaten in a variety of ways, but most in salads or cooked in a sauce for pasta, it is included as one of the dishes prepared for the Feast of the Seven Fishes. In East Asian cuisines, this seafood is cut into thin slices and steamed or stir-fried. Eighty-percent of the queen conch meat in international trade is imported into the United States; the Florida Keys were a major source of queen conchs until the 1970s, but the conchs are now scarce and all harvesting of them in Florida waters is prohibited. Conch shells can be used as wind instruments, they are prepared by cutting a hole in the spire of the shell near the apex, blowing into the shell as if it were a trumpet, as in blowing horn. Sometimes, a mouthpiece is used. Pitch is adjusted by moving one's hand out of the aperture. Various species of large marine gastropod shells can be turned into "blowing shells", but some of the best-known species used are the sacred chank or shankha Turbinella pyrum, the Triton's trumpet Charonia tritonis, the queen conch Strombus gigas.
Many different kinds of mollusks can produce pearls. Pearls from the queen conch, S. gigas, are rare and have been collectors' items since Victorian times. Conch pearls occur in a range of hues, including white and orange, with many intermediate shades, but pink is the colour most associated with the conch pearl, such that these pearls are sometimes referred to as "pink pearls". In some gemological texts, non-nacreous gastropod pearls used to be referred to as "calcareous concretions" because they were "porcellaneous", rather than "nacreous", sometimes known as "orient"; the GIA and CIBJO now use the term "pearl"—or, where appropriate, the more descriptive term "non-nacreous pearl"—when referring to such items, under Federal Trade Commission rules, various mollusc pearls may be referred to as "pearls" without qualification. Although not nacreous, the surfaces of fine conch pearls have a unique and attractive appearance of their own; the microstructure of conch pearls comprises aligned bundles of microcrystalline fibres that create a shimmering iridescent effect known as "flame structure".
The effect is a form of chatoyancy, caused by the interaction of light rays with the microcrystals in the pearl's surface, it somewhat resembles moiré silk. Conch shells are sometimes used as decoration, as decorative planters, in cameo making. In classic Maya art, conchs are shown being used in many ways, including as paint and ink holders for elite scribes, as bugles or trumpets, as hand weapons. Conch shells have been used as shell money in several cultures; some American Aboriginals used cylindrical conch columella beads as part of breastplates and other personal adornment. In India, the Bengali bride-to-be is adorned with conch shell and coral bangles