Calcite

Calcite

Calcite
 

 

 

 

 

 

 


 

 

 

 

Composition: Calcium carbonate (CaCO3)

Synonyms/Varieties:
Baricalcite
Cave Pearls
Dogtooth Spar
Dolomitic Calcite Point
Iceland Spar
Lublinite
Manganocalcite
Nailhead Spar
Plumbocalcite
Sand-calcite
Satin Spar
Slate Spar
Stinkkalk
Strontianocalcite

Physical Properties:
Color: White to colorless, tinted gray, red, green, blue, yellow, brown to black
Streak: White to grayish
Luster: Vitreous, pearly, greasy
Hardness: 3
Tenacity: Brittle
Specific Gravity: 2.71
Cleavage: Perfect, three directions

Crystallography:
System: Hexagonal
Twinning: Common
Habit: Crystals are extremely varied. Aggregates are massive, fibrous, granular, stalactitic, and chalky.

General Information:
Calcite is a relatively soft mineral, and can be scratched by a copper pennv. Its three perfect cleavages yield characteristics rhomb-shaped p fragments bounded by flat, shiny surfaces. The mineral is easily soluble in acids, with liberation of carbon dioxide (CO2) making the reaction effervescent. Since this reaction can be observed even when weak acids like vinegar (acetic acid) are put on calcite powder, it-is a good test for the mineral. Calcite is often confused with quart%, but can easily be scratched with a knife whereas quartz cannot. Calcite is one of the most common minerals of the earth's crust. It is the predominant mineral comprising such abundant rocks as limestone and marble, and also occurs as a subordinate constituent in many other rocks. White veins of pure calcite can be found penetrating various rocks in many areas of California. Calcite has numerous uses as the predominant constituent of time- stone, so these are mentioned under the description of that rock. Large water-clear crystals or cleavage rhombs of calcite are called Iceland spar. Such crystals give a double image of things viewed through them, and are of value for the manufacture of various optical instruments, particularly in the production of Nicol prisms to produce polarized light. Name is from the Latin word calx, meaning lime.

California Counties in Which this Mineral is Found
 

Alameda
Alpine
Calaveras
El Dorado
Fresno
Imperial
Inyo
Kern
Lake
 
Los Angeles
Madera
Marin
Mariposa
Merced
Modoc
Mono
Monterey
Nevada
Riverside
San Benito
San Bernardino
San Diego
San Francisco
Santa Barbara
Santa Cruz
Shasta
Stanislaus
Trinity
Tulare
Tuolumne
Ventura
 

Information on Specimen Photo:
Specimen Description: Calcite crystal, 5 in. long, Tri-State lead and zinc deposit.