5.6" Quartz Crystals On Sparkling Bladed Hematite - See Video!
This is a phenomenal association of quartz crystals, bladed hematite rosettes (specularite) and calcite, collected from the Lechang Mine in Guangdong, China. The quartz crystals are all in pristine condition, many of which are encrusted in calcite crystals. A couple of the quartz crystals' growth were interrupted by blades of calcite. This unusual growth form is known as "interrupted quartz" and results in oddly shaped crystals.
Hematite is a fairly common mineral, typically responsible for the red-brown coloration that can be found in other minerals and rocks. The chemical composition of hematite is Fe2O3, occasionally containing small amounts of titanium (variable formula (Fe,Ti)2O3). Much of the time, non-crystalline hematite specimens are the result of a transformation from limonite following loss of water.
Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.
Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.