Grigore Cobălcescu Museum of Mineralogy and Petrography has more than 25,000 samples of minerals, gemstones, and rocks from all over the world. Most of them come from the territory of Romania and cover all the mineral classes and common igneous, metamorphic, and sedimentary rocks.
Pyrite is a very common mineral. Pyrite’s brassy golden color led to it being called “Fool’s gold”, but the name of the Pyrite comes from the Greek word pyr meaning “fire” because sparks flew from it when struck with another mineral or metal.
Marcasite is the orthorhombic polymorph (the same chemical formula, but different crystal system) of isometric (cubic) Pyrite. This is a beautiful specimen of pale brass-yellow Marcasite crystals with an unique pagoda-like shape.
AGATE (VARIETY OF CHALCEDONY)
Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of Quartz. Banded Chalcedonies (a sub-variety of Quartz, whether parallel or concentric) are called Agates.
The translucent purple to violet variety of the mineral Quartz; used as a jeweler’s stone. Amethyst is very common in many different geological environments. This specimen has hematite inclusions.
GYPSUM (DESERT ROSE)
Rose-like aggregate of tabular brown gypsum crystals formed by precipitation in (usually) arid desert regions containing trapped sand particles. The desert rose formation was Jean Nouvel’s inspiration for the National Museum of Qatar architecture (Doha).
Aragonite is a carbonate mineral, orthorhombic mineral species of calcium carbonate but with a crystal structure different from those of Vaterite and Calcite. Aragonite it is also known as Aragon spar.
HIGHLY VESICULAR SCORIA
Scoria is a highly vesicular dark colored volcanic rock that may or may not contain crystals (phenocrysts). Scoria is typically dark in color (generally dark brown, black or purplish red), and basaltic or andesitic in composition.