Minerals
A mineral is a naturally occurring chemical compound usually of crystalline form and not produced by life processes. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids. The study of minerals is called mineralogy. To meet the definition of “mineral” used by most geologists, a substance must meet five requirements:
Fluorite (Fluorspar)
Fluorite, also called fluorspar, common halide mineral, calcium fluoride (CaF2), which is the principal fluorine mineral. It is usually quite pure, but as much as 20 percent yttrium or cerium may replace calcium. Fluorite occurs most commonly as a glassy, many-hued vein mineral and is often associated with lead and silver ores; it also occurs in cavities, in sedimentary rocks, in pegmatites, and in hot-spring areas
Halite
Culinary rock salt is actually halite. Its name is derived from the Greek word hals, which means “salt.” Most halite is colorless, white, gray, orange, or brown, but it can also be bright blue or purple. The orange color comes from inclusions of hematite, while the blue and purple colors indicate defects in the crystal structure.
Gypsum
Gypsum, common sulfate mineral of superb industrial significance, composed of hydrated calcium sulfate (CaSO4 ·2H2O). In properly-developed crystals the mineral normally has been called selenite. The fibrous large variety has a silky lustre and is known as satin spar
Anhydrite
Anhydrite is one of the minerals that make up the rocks. Chemical structure similar to Gypsum but does not contain water. Formula is CaSO4.There is a sedimentary basin in large areas where sea water evaporates. It is usually found in salt deposits with gypsum next to it. Anhydrite may form on the coastline or tidal flat deposits caused by the evaporation of seawater.
Barite
The barium sulfate barite takes its name from the Greek word barys, which means “heavy” a reference to its high specific gravity. It has also been called heavy spar. Barite crystals are sometimes tinged yellow, blue, or brown. Golden barite comes from South Dakota. Crystals are well formed, usually either prismatic or tabular.
Molybdenite
A molybdenum sulfide, molybdenite is the most important source of molybdenum, which is an important element in high-strength steels. Molybdenite was originally thought to be lead, and its name is derived from the Greek word for lead, molybdos. It was recognized as a distinct mineral by the Swedish chemist Carl Scheele in 1778.
Pyrite (Fool’s Gold)
Known since antiquity, pyrite is commonly referred to as “fool’s gold.” Although much lighter than gold, its brassy color and relatively high density misled many novice prospectors. Its name is derived from the Greek word pyr, meaning “fire,” because it emits sparks when struck by iron.
Stibnite
The principal ore of antimony, stibnite is antimony sulfide. Its name comes from the Latin stibium. Lead-gray to silvery gray in color, it often develops a black, iridescent tarnish on exposure to light. It normally occurs as elongated, prismatic crystals that may be bent or twisted.
Orpiment
An arsenic sulfide, orpiment is a soft yellow or orange mineral. Widely distributed, it is typically powdery or massive, but it is also found as cleavable, columnar, or foliated masses. Distinct crystals are uncommon, but when found they are short prisms.
Realgar (Ruby Sulfur)
An important ore of arsenic, realgar is bright red or orange in color. Crystals are not often found, but when they occur they are short, prismatic, and striated. Realgar mostly occurs as coarse to fine granular masses and as encrustations.
Cinnabar (Mercury)
A mercury sulfide, cinnabar takes its name from the Persian zinjirfrah and Arabic zinjafr, which mean “dragon’s blood.” It is bright scarlet to deep grayish red in color. It is the major source of mercury.
Chalcopyrite
Chalcopyrite is a copper include sulfide mineral .It has to formula CuFeS2.It is usually seed brassy to golden yellow color .Also copper is most important ore mineral thousands of years. Hardness of 3.5 – 4 on the Mohs scale and diagnostic properties streak is black green