Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.
Page from Treatise on mineralogy by Friedrich Mohs (1825)
Calcite is a carbonate mineral (CaCO3) with a rhombohedral crystal structure.
Aragonite is an orthorhombic polymorph of calcite.
The perovskite crystal structure. The most abundant mineral in the Earth, bridgmanite, has this structure. Its chemical formula is (Mg,Fe)SiO3; the red spheres are oxygen, the blue spheres silicon and the green spheres magnesium or iron.
Gaius Plinius Secundus, called Pliny the Elder, was a Roman author, naturalist, natural philosopher, naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic Naturalis Historia, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field.
One of the Xanten Horse-Phalerae located in the British Museum, measuring 10.5 cm (4.1 in). It bears an inscription formed from punched dots: PLINIO PRAEF EQ; i.e., Plinio praefecto equitum, "Pliny prefect of cavalry". It was perhaps issued to every man in Pliny's unit. The figure is the bust of the emperor.
City and Lake of Como, painted by Jean-Baptiste-Camille Corot, 1834
Colossal head of Titus, son of Vespasian. Glyptothek, Munich