The chemical formula of mineral Calomel is indicated by HgCl or Mercury Chloride. Calomel is actually a Halide mineral. It is also referred to as the mineral horn quicksilver or horn mercury. Before the twentieth century, Calomel was used as a medicine internally for laxation and for disinfection. This mineral species Calomel was actually first discovered in the year 1612 at the Landsberg Mountain in Germany. It has been thought that the name of the mineral species Calomel is of Greek in origin. It has been thought that the name was derived from the Greek word kalos, which means “beautiful” and melas, which means “black”. This is may be an allusion to its blackening with ammonia. Mineral Calomel is a considerably rare mineral. This Calomel mineral is never found in large quantities in any of its types of locality. Calomel is known to crystallize in the tetragonal system. In optical mineralogy, this tetragonal system comprises crystals having three axes, which are all in a position perpendicular to one another. Two axes are usually found having the same or equal length.
Specimens of Calomel are commonly found in shades of white, gray or yellow in transmitted light of petrographic polarizing light microscope. Calomel commonly displays very high luster when it is viewed in reflected light of petrographic polarizing microscope. It is actually found exhibiting adamantine luster in reflected light of petrographic polarizing light microscope. Calomel mineral specimens are usually found having indistinct cleavage in only one direction when it is evaluated between crossed nicols of polarizing light microscopes for mineralogists. Calomel is most commonly found exhibiting conchoidal fracture when it is viewed under several adjustments on the aperture diaphragm of petrographic polarizing microscopes used in optical mineralogy. The specific gravity measure for Calomel mineral usually gives a value that is commonly ranging from 6.4 grams per cubic centimeters to 6.5 grams per cubic centimeters, which is considered very heavy for translucent minerals. The hardness measure of mineral specimen Calomel using the Mohs scale method is usually ranging from 1 to 2. When they are rubbed on a white porcelain streak plate, they are commonly found leaving a white streak.
Calomel crystals are commonly found translucent in appearance. The crystal habit of mineral Calomel as described in optical mineralogy commonly include small tabular to pyramidal or hornlike crystals, which are very nice and interesting to view under polarized light microscopes. These crystals are usually seen as coatings or crusts on other minerals and are splendidly exhibiting attractive microscope images under polarizing light microscopes for mineralogists. Some attractive specimens of mineral Calomel show a nice and interesting fluorescent red under ultraviolet light. And these crystals darken upon prolonged exposure to light over time. Calomel is commonly found coating other minerals. Calomel crystals are considered as somewhat sectile. Sectile crystals are often found with curved shavings and scrapings produced by a knife blade. Some Calomel crystals are equant are they may be sometimes found with complex twins. The crystals are often found as contact or interpenetrant twins, which are often repeated and with irregular and concealed boundaries.
Calomel mineral is most commonly found displaying a very high surface relief when it is evaluated under a polarizing light microscope for mineralogists. Calomel mineral is most commonly found exhibiting a uniaxial positive figure when it is closely evaluated under petrographic polarizing microscope. Refractive indices of Calomel is most commonly found ranging from 1.970 to 2.650. Calomel also exhibits a weak pleochroism when it is viewed with the aid of petrographic polarizing light microscope. The maximum birefringence of Calomel is found to be 0.680. Calomel mineral specimen shows a brick red fluorescent color in ultraviolet light. Calomel mineral contains mercury hand washing after handling them is advised. When breaking or handling the Calomel mineral specimen, avoid inhaling dusts. Never ingest or lick the material. Calomel powder is insoluble in water, alcohol or ether.
Calomel minerals are commonly associated with several other interesting minerals such as cinnabar, mercury, metacinnabar and several other mercury minerals. The best field indicators of mineral Calomel usually include density, crystal habit, fluorescence, hardness and its awesome association with several other wonderful and interesting minerals. Calomel is often considered as a secondary mineral, which is formed from the alteration of mineral cinnabar or other mercury minerals. Calomel minerals are also found deposited from hot underground solutions. They are also found in oxidized mercury deposits. Calomel minerals notably occur at some types of localities including some areas in the United States such as Oregon, Arkansas, Terlingua, Texas, New Idria, and California. And they can be also found in Hunan Province in China, Idria in Serbia and also at Almaden in Spain.
