Coloradoite

Coloradoite, a member of the coordination subclass of tellurides, is a covalent compound that is isostructural with sphalerite (ZnS).

Jackson was the first to discover an American mineral containing the element tellurium in the Whitehall mine, in Spotsylvania County, near Fredericksburg, Virginia.

Theoretically the composition (%) of HgTe is Hg 61.14, Te 38.86;[11] Table 1 shows results from a chemical analyses reported by Vlasov on samples collected from two different locations.

[2] It is a covalent compound with a high proportion of metallic bonding, due to its low valencies and even lower interatomic distances.

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.

[2] 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.

[13] Reactions with HCl, KCN, KOH and HgCl2 yield no precipitates or residue as opposed to petzite which turns dark brown with HNO3.

Later studies showed its existence in other mines of the region as well as Kalgoorlie, Australia and Kirkland Lake District, Canada.