CALCITE

HISTORY, NAME, LOCALITIES: Although known since antiquity, calcite’s many confusing crystal habits precluded recognition as a species until 1845.  Its name stems from the Greek chalx, meaning “lime.” Calcite is found worldwide; notable collecting localities are in England, Iceland, Germany, India, and the United States (Tennessee, Missouri, Michigan, New Jersey).

MINERALOGY, PROPERTIES, OCCURRENCE: Calcite [calcium carbonate, CaCO₃], pronounced CHAL-site, is the most abundant carbonate mineral.  It crystallizes in the hexagonal system (trigonal subsystem); crystals are usually rhombohedral, scalenohedral, or prismatic with a unusually wide variety of habits.  It has a Mohs hardness of 3.0, perfect cleavage in three directions to form rhombohedrons, vitreous-to-dull luster, and a specific gravity of 2.7-3.0.  It is usually white or colorless, but impurities create a wide range of pale colors.  Calcite develops in many mineralogical environments, including pegmatites, carbonatites, chemical and sedimentary rocks, metamorphic rocks, and hydrothermal veins.

METAPHYSICAL PROPERTIES, LORE, USES: According to metaphysical practitioners, calcite enhances learning abilities, reduces fear and stress, removes negative energies, and promotes creativity and imagination.  Calcite is the primary mineral component of limestone, which is mined in huge quantities for use as dimensional stone, in cement, and as a metallurgical flux; and marble, which serves as a dimensional stone and sculpting medium.  Banded, massive forms of calcite, known as “marble onyx,” are fashioned into ornamental objects.

COLLECTORS’ INFORMATION: Calcite specimens are widely sought by collectors for their remarkable variety of crystal habits and colors, unusual size, affordability, excellent crystal development, and, in composite specimens, interesting associations with many other minerals

DOLOMITE

HISTORY, NAME, LOCALITIES: Dolomite was described as a mineral species in 1791 and named for the French geologist Déodat de Dolomieu.  Dolomite is abundant and widely distributed, but good specimens are uncommon.  Notable sources are found in China, Austria, France, Germany, Morocco, South Africa, and the United States (Missouri, Illinois, Alabama, Georgia, New York).

MINERALOGY, PROPERTIES, OCCURRENCE: Dolomite [calcium magnesium carbonate, CaMg(CO₃)₂], pronounced DOUGH-low-mite, crystallizes in the hexagonal system (trigonal subsystem) as blocky, often twinned, rhombohedral crystals with slightly curved faces.  Dolomite also occurs in compact, granular, and massive forms and is the primary component of dolomite rock, which is similar to limestone.  It has a Mohs hardness of 3.5-4.0, pearly to vitreous luster, perfect cleavage in three directions to form rhombohedrons, and a specific gravity of 2.8-2.9.  Crystals, which are rarely well-developed, are transparent to translucent and usually white or colorless, although impurities can impart a range of subtle hues.  It occurs primarily in chemical sedimentary rocks (dolomite rock) and in metamorphosed dolomitic marbles.  It also is  found in metamorphic skarns and hydrothermal veins.

METAPHYSICAL PROPERTIES, LORE, USES:  According to modern metaphysical practitioners, dolomite relieves sorrow and the symptoms of depression, aligns and balances mental and emotional energies, and encourages charitable actions and generosity.  Dolomite is an important ore of magnesium and magnesium compounds; dolomite rock is quarried as a dimensional stone, cement aggregate, and road-fill material.

COLLECTORS’ INFORMATION: Collectors acquire dolomite because of the rarity of well-developed crystals; interesting mineralogical associations; and unusual, curved crystal faces.