How do I identify Coloradoite?

Coloradoite can be identified by its hardness of 2.5 on the Mohs scale, Iron black tending toward gray color. Look for these key characteristics when examining specimens.

What color is Coloradoite?

Coloradoite typically appears in Iron black tending toward gray. Color can vary depending on impurities and formation conditions.

How hard is Coloradoite?

Coloradoite has a hardness of 2.5 on the Mohs scale. This makes it a soft mineral that can be scratched easily.

Coloradoite

A variety of Minerals

What is Coloradoite?

Coloradoite, also known as mercury telluride (HgTe), is a rare telluride ore associated with metallic deposit (especially gold and silver). Gold usually occurs within tellurides, such as coloradoite, as a high-finess native metal. The quest for mining led to the discovery of telluride ores which were found to be associated with metals. Tellurides are ingrown into ores containing these precious metals and are also responsible for a significant amount of these metals being produced. Coloradoite, a member of the coordination subclass of tellurides, is a covalent compound that is isostructural with sphalerite (ZnS). Its chemical properties are highly instrumental in distinguishing it from other tellurides. It was first discovered in Colorado in 1877. Since then, other deposits have been found. Although it plays an important role in the geology of minerals, it can also be used for other purposes.

Coloradoite Market Value Calculator

Estimate the market value of Coloradoite using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Coloradoite Localities Map

See where Coloradoite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview

North ZoneCentral RidgeSouth Basin

Key Characteristics

Characteristics of Coloradoite

Coloradoite is a brittle, massively granular mineral, with a hardness of 2.5. It has a metallic luster, which could be explained by the presence of metallic bonding in the crystal. Its specific gravity is 8.10 and is an opaque mineral with colors iron-black inclining to gray; in polished sections, and white with slight grayish brown tint, tarnishing to dull purple. Its fracture is uneven to subconchordial with a cell length of 6.44 angstroms. For ease of identification, its etching tests are as follows; With HNO3 it slowly produces a weak brown variegated deposit that acts as a protector to the surface and can be removed completely; with aqua regia it effervesces and produces a weak deposit that can be rubbed off and white, radiating spherules are formed, reaction with FeCl3 yields a browning of the surface at different rates and produces black rims of droplet. Reactions with HCl, KCN, KOH and HgCl2 yield no precipitates or residue as opposed to petzite which turns dark brown with HNO3.

Composition of Coloradoite

The chemical formula for coloradoite is HgTe. Theoretically the composition (%) of HgTe is Hg 61.14, Te 38.86; Table 1 shows results from a chemical analyses reported by Vlasov on samples collected from two different locations. Because it is found with other telluride ores, it carries some other metals like gold and silver. In its pure form, it has the composition mentioned above. A little hard to identify, petzite which is hazardous could be mistaken for coloradoite, on the other hand, petzite is anisotropic as opposed to coloradoite being an isotropic mineral. It is a binary compound with the general formula AX.