2.1" Quartz Crystals with Calcite & Loellingite - Inner Mongolia

This is a beautiful cluster of quartz crystals with metallic loellingite, arsenopyrite and bladed calcite. It comes from the Huanggang Fe-Sn Deposit in Inner Mongolia.

The "Huanggang Mine" is a complex of seven somewhat interconnected mines that are located near Chifeng City, Inner Mongolia, China. Incredible mineral specimens started coming out of this mining complex around 2009, however, the location provided for the specimens was a long ways away from the actual site. This is a practice commonly performed by dealers/miners following a new discovery to try and preserve the mineral site's true location and/or for political purposes.

As the popularity of the site increased, more and more fascinating specimens were popping up on the market. Some of the earlier minerals included world-class ilvaite crystals, pink fluorite octahedrons, hedenbergite included quartz (many of which were discarded at first) and arsenopyrite. Over the following years, garnets, pink manganoan calcite, gorgeous fluorites, sphalerite, löllingite, borcarite, scheelite and a variety of other minerals began to surface on the market. To this day, new mineral discoveries are made in these mines.

A brief description of the mine and minerals from the Huanggang Deposit.

loellingite (or löllingite) is an iron arsenide mineral with the chemical formula FeAs₂. It typically forms in association with arsenopyrite and can be difficult to tell the two apart. The crystals are often twinned and exhibit a silvery metallic luster. It is named after the Lölling mining district in Carinthia, Austria, the site from which it was first described in 1845.

Toxicity Warning: Loellingite contains arsenic and can be harmful if inhaled or swallowed. Most of the risk is long-term, chronic exposure to its dust or fumes. While a crystal sitting on your shelf doesn't pose a health risk you should wash your hands after handling and keep out of reach of children.

Arsenopyrite is an iron arsenic sulfide with the chemical formula FeAsS. Depending on minerals present during formation, the iron can be replaced by cobalt (Cobaltite). Arsenopyrite is the most common mineral containing arsenic and can be found in igneous, metamorphic and sedimentary rock. Crystals can be found as prismatic, twinned, columnar, elongated and massive formations within veins and are found in locations all around the world.

Arsenopyrite contains a significant amount of poisonous arsenic, making it somewhat toxic. Therefore, washing hands following handling of arsenopyrite specimens, is recommended.

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.
Quartz, Calcite, Arsenopyrite & Loellingite
Huanggang Fe-Sn deposit, Chifeng City, Inner Mongolia, China
2.1" wide