The chemical composition of the mineral Greenockite is indicated by the formula CdS, a Cadmium Sulfide. This Greenockite belongs to the Sulfides mineral class. Greenockite is considered as a minor ore of cadmium and it is often found exhibiting nice and interesting appearance when viewed under ore polarizing microscopes. Greenockite is also used as mineral specimen and it is most commonly found exhibiting nice and wonderful microscope image when viewed under polarized light microscopes. Mineral Greenockite is actually the only real ore of cadmium and Greenockite is unfortunately a very rare mineral species. Greenockite is most sought after by most mineral collectors because of its rarity and for its interesting color and crystal habit exhibited under polarized light microscopes. The structure of mineral Greenockite is the same as that of the zinc iron sulfide mineral called wurtzite. Greenockite mineral crystals are typically found as six sided pyramids. This habit usually exhibits the hemimorphic character of Greenockite as the top of the crystal is the point and the bottom of the crystal is the base of the pyramid. Greenockite mineral crystals can be also found in platy forms with a hexagonal outline when viewed under polarizing microscopes. In this case, the hemimorphic character of Greenockite is not easily distinguished.
Mineral Greenockite was actually first recognized in Bishop, Scotland in year 1840. It was discovered during the cutting of a tunnel for the Glasgow, Paisley and Greenock Railway. Mineral Greenockite was named after the land owner,
Mineral Greenockite is most commonly found in honey yellow, orange, red or light to dark brown in color when viewed under geological polarizing microscopes. The luster that is most commonly exhibited by the mineral Greenockite in reflected light of polarized microscope is usually adamantine to resinous. Greenockite has poor basal cleavage found in one direction and good prismatic cleavage in three directions when the mineral is evaluated under geological polarizing light microscopes. The fracture that is most commonly found visible when mineral Greenockite is viewed under polarized microscope is usually conchoidal. The hardness measure of the mineral Greenockite when it is evaluated using the Mohs scale method is usually ranging from 3 to 3.5. When mineral section of Greenockite is rubbed on a white porcelain streak plate, it is most commonly found leaving a red, orange or light brown streak. The specific gravity measure of the mineral Greenockite usually gives an approximate value ranging from 4.5 grams per cubic centimeters to 5.0 grams per cubic centimeters, which is considered much heavier than average value.
Mineral Greenockite is known to crystallize in the hexagonal system, which is commonly seen clearly exhibited when the mineral is evaluated under geological polarizing microscopes. The hexagonal system of crystallization comprises crystals having four axes. Three of which are positioned in a single plane with equal length and are symmetrically spaced. The fourth axis is found to be perpendicular to the other three axes. Most Greenockite mineral crystals are found transparent to translucent in appearance. The crystal habit of the mineral usually include small tapering hemimorphic six sided pyramids that are commonly found fascinating when viewed with the aid of petrographic polarizing light microscopes. Greenockite can be also found in platy hexagonal crystals. It can be also seen as crusts or dustings over crystals of other minerals like calcite, sphalerite and smithsonite. Sometimes Greenockite crystals can be found in form of colloform or forming from a gel or colloidal mass. Sometimes Greenockite can be also found in radial aggregates where crystals radiate from the center without producing stellar forms.
When mineral Greenockite is evaluated between crossed nicols of polarized light microscopes, it is most commonly found having uniaxial negative figure. It is also a dichroic mineral and it commonly exhibits dichroic colors in shades of blue, green and red when the mineral is evaluated under geological polarizing microscopes. There can be possible occurrence of striations on the pyramidal faces parallel to base when Greenockite mineral crystal is evaluated under petrographic polarizing light microscopes. The index of refraction found exhibited by the mineral in plane light of geological polarizing microscope is usually ranging from 2.50 to 2.52. The maximum birefringence of the mineral Greenockite in plane light of geological polarizing microscope is 0.023. When specimen of Greenockite is evaluated under several adjustments on the aperture diaphragm of the petrographic polarizing microscope, it is commonly found exhibiting very high surface relief. It also exhibits weak pleochroism in plane-polarized light of polarizing microscopes for geologists. Greenockite crystals are usually found soluble in Hydrochloric Acid and more importantly, giving off hydrogen sulfide gas. Greenockite mineral is most commonly associated with other mineral including prehnite, fluorite, marcasite, chalcopyrite, sphalerite, quartz, pyrite, smithsonite and calcite. This mineral species contains cadmium, thus it is highly recommended to hand wash after handling the material. Also avoid inhaling of its dust or breaking. Never lick or ingest the mineral crystals. Greenockite is a nonmagnetic mineral species. Greenockite is not radioactive.
Mineral Greenockite usually occurs with other sulfide minerals. Greenockite can be also found in traprock cavities and ore veins. The best field indicators of mineral Greenockite usually include color, cleavage, crystal habit and streak. Greenockite mineral notably occurs at several types of localities including Llallagua in Bolivia, Greenock in Scotland and some areas in the United States including Paterson in New Jersey, Joplin in Missouri, Arkansas, Illinois and Kentucky.