SUMMARY / RELATED TOPICS

Hematite

Hematite spelled as haematite, is a common iron oxide with a formula called Fe2O3 and has been widespread in rocks and soils. Hematite forms in the shape of crystals through the rhombohedral lattice system, it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above 950 °C. Hematite is colored brown to reddish-brown, or red, it is mined as the main ore of iron. Varieties include kidney ore, iron rose and specularite. While these forms vary, they all have a rust-red streak. Hematite is much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral. Large deposits of hematite are found in banded iron formations. Gray hematite is found in places that can have still, standing water or mineral hot springs, such as those in Yellowstone National Park in North America; the mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can occur without water as the result of volcanic activity.

Clay-sized hematite crystals can occur as a secondary mineral formed by weathering processes in soil, along with other iron oxides or oxyhydroxides such as goethite, is responsible for the red color of many tropical, ancient, or otherwise weathered soils. The name hematite is derived from the Greek word for blood αἷμα, due to the red coloration found in some varieties of hematite; the color of hematite lends itself to use as a pigment. The English name of the stone is derived from Middle French hématite pierre, imported from Latin lapis haematites c. the 15th century, which originated from Ancient Greek αἱματίτης λίθος. Ochre is a clay, colored by varying amounts of hematite, varying between 20% and 70%. Red ochre contains unhydrated hematite; the principal use of ochre is for tinting with a permanent color. The red chalk writing of this mineral was one of the earliest in the history of humans; the powdery mineral was first used 164,000 years ago by the Pinnacle-Point man for social purposes. Hematite residues are found in graves from 80,000 years ago.

Near Rydno in Poland and Lovas in Hungary red chalk mines have been found that are from 5000 BC, belonging to the Linear Pottery culture at the Upper Rhine. Rich deposits of hematite have been found on the island of Elba that have been mined since the time of the Etruscans. Hematite is an antiferromagnetic material below the Morin transition at 250 K, a canted antiferromagnet or weakly ferromagnetic above the Morin transition and below its Néel temperature at 948 K, above which it is paramagnetic; the magnetic structure of α-hematite was the subject of considerable discussion and debate during the 1950s, as it appeared to be ferromagnetic with a Curie temperature of 1,000 K, but with an small magnetic moment. Adding to the surprise was a transition with a decrease in temperature at around 260 K to a phase with no net magnetic moment, it was shown that the system is antiferromagnetic, but that the low symmetry of the cation sites allows spin–orbit coupling to cause canting of the moments when they are in the plane perpendicular to the c axis.

The disappearance of the moment with a decrease in temperature at 260 K is caused by a change in the anisotropy which causes the moments to align along the c axis. In this configuration, spin canting does not reduce the energy; the magnetic properties of bulk hematite differ from their nanoscale counterparts. For example, the Morin transition temperature of hematite decreases with a decrease in the particle size; the suppression of this transition has been observed in hematite nanoparticles and is attributed to the presence of impurities, water molecules and defects in the crystals lattice. Hematite is part of a complex solid solution oxyhydroxide system having various contents of water, hydroxyl groups and vacancy substitutions that affect the mineral's magnetic and crystal chemical properties. Two other end-members are referred to as hydrohematite. Enhanced magnetic coercivities for hematite have been achieved by dry-heating a two-line ferrihydrite precursor prepared from solution. Hematite exhibited temperature-dependent magnetic coercivity values ranging from 289 to 5,027 oersteds.

The origin of these high coercivity values has been interpreted as a consequence of the subparticle structure induced by the different particle and crystallite size growth rates at increasing annealing temperature. These differences in the growth rates are translated into a progressive development of a subparticle structure at the nanoscale. At lower temperatures, single particles crystallize however. Hematite is present in the waste tailings of iron mines. A developed process, uses magnets to glean waste hematite from old mine tailings in Minnesota's vast Mesabi Range iron district. Falu red is a pigment used in traditional Swedish house paints, it was made from tailings of the Falu mine. The spectral signature of hematite was seen on the planet Mars by the infrared spectrometer on the NASA Mars Global Surveyor and 2001 Mars Odyssey spacecraft in orbit around Mars; the mineral was seen in abundance at two sites on the planet, the Terra Meridiani site, near the Martian equator at 0° longitude, the Aram Chaos site near the Valles Marineris.

Several other sites showed hematite, suc

Rifle Camp Park

Rifle Camp Park is a 225-acre county park of Passaic County, New Jersey. It is located within Woodland Park, but its eastern edge extends into Clifton as well; the park includes hiking trails, an observatory, nature center, fitness trail, amphitheater, a bird watching blind, an overnight camping facility for local scout organizations. Rifle Camp Park was established from the same land acquired for the creation of the nearly adjacent Garret Mountain Reservation; the land was part of the estate of Catholina Lambert, the owner of a silk mill in Paterson. After Lambert’s death in 1923, the estate was sold to the City of Paterson, which transferred the land to Passaic County in 1928. In 1929, landscape architect firm Olmsted Associates, the successor to the practice of Frederick Law Olmsted, was commissioned with the development of the parkland, completing work in 1934. Since the division of the Lambert estate between Garret Mountain Reservation and Rifle Camp Park, it has been proposed to connect the two.

As of 2011, the Borough of Woodland Park has been discussing ways to link the adjacent properties. The area of Rifle Camp Park served as a location where Washington’s troops could observe British movements during the Revolutionary War in 1780; the name ‘Rifle Camp’ comes from the fact that Major James Parr’s rifle corps camped for a short time in the vicinity of the Great Notch, just to the south of what would become the park. Parr and his riflemen achieved notice in the Sullivan Expedition in 1779. In October, 1780, Parr and his rifle corps had been assigned to protect the strategic pass at the Great Notch from British incursion, but stayed for just one week. On October 17, 1780, the rifle corps left the area, being ordered to join General Lafayette’s Light Corps in the vicinity of present-day Goffle Brook Park on the opposite side of the Passaic River; the land that would become Rifle Camp Park was host to the farm of Thomas Ryder, a loyalist. It is at Ryder’s farm that Joshua Hett Smith, a lawyer from Haverstraw, New York who aided the treasonous Benedict Arnold and British Major John André, was granted hospitality during his escape from American imprisonment.

Rifle Camp Park sits on the ridgeline of a section of First Watchung Mountain. It is extensively forested. Due to the local geology, large trap rock outcrops are abundant throughout the property; the eastern limit of the parkland consists of nearly vertical basalt cliffs that provide panoramic views of the surrounding area. To the west is the Great Notch Reservoir, whose headwaters lie within the park and comprise the source of the Third River. Along the south end of the park there is a former quarry being turned over to housing development; the park is accessed via Rifle Camp Road in Woodland Park, near the intersection with Overmount Ave. The main driveway leads to five parking areas, with the first area adjacent to the amphitheater and the fifth area adjacent to the observatory/nature center. Garret Mountain Reservation Rifle Camp Park Nature Center and Observatory Information

NGC 4586

NGC 4586 is a spiral galaxy located about 50 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on February 2, 1786. Although listed in the Virgo Cluster Catalog, NGC 4586 is considered to be a member of the Virgo II Groups which form a southern extension of the Virgo cluster. NGC 4586 is in the process of infalling into the Virgo Cluster and is predicted to enter the cluster in about 500 million years. NGC 4586 has a peanut-shaped bulge; the bulge has been interpreted to be a bar viewed edge-on. List of NGC objects NGC 4469 NGC 4013 NGC 4586 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Sky Map and images