Gemstone :
Calcite

Birthstone Month :
Calcite is not associated with any particular birthstone month.

Zodiac :
Calcite is not associated with any particular zodiac sign.

Chemical Symbol :
CaCO3

Chemical Make-up :
Calcite is a stable form of the mineral Calcium Carbonate, and is the primary mineral in limestone & marble.

History & Lore :
The name Calcite is a derivation of the Greek word for lime, “chalix”.

Availability :
Calcite is one of the most commonly found minerals on earth, and is believed to be responsible for accounting for up to 4% of the weight of the earth's crust. Owing to the extremely wide distribtion of Calcite deposits, and the wide range of situations in which it forms, Calcite is available in huge and diverse number of varieties, with the most well-known varieties being known as “Dogtooth Spar”, “Iceland Spar” and
“Mexican Onyx”.

Sources :
Calcite deposits are abundant, with instances occuring worldwide in locations including, Africa, Brazil, England (Cornwall, Durham, Lancashire), Germany, Iceland, India, and many of the United States.

Evaluation :
Calcite is rated at 3 on the Moh's Scale of Hardness, and is a very soft gemstone. Because of it's softness Calcite is best used for earrings, pendants, brooches, or other applications where it will not be subjected to knocks / scratches.

Calcite is found in a great number of colors including, black, blue, brown, colorless, green, lavendar, pink, red, yellow and white. In addition to this, Calcite can also be found in bi, tri and multi-colored varieties. Calcite coloration is caused by impurities within its crystals.

Calcite is usually transparent to opaque and some varieties exhibit fluorescence or phosphorescence, with specimens displaying beautiful bright colors when exposed to UV light. In fact, some examples continue to glow with color (phosphoresce), even after the UV source has been removed. In addition to this Calcite has a unique property, double refraction. What this means is that when rays of light enter the stone it is split, creating fast and slow beams of light. This causes the effect of anything and everything being viewed through Calcite appearing twice. This unique double refraction can also cause a rainbow effect in examples that have small crystal fractures.

The Calcite variety “Dogtooth Spar” is named so because of its shape which resembles a dogs tooth. Amber- orange and clear or colorless varieties are considered “classic”, with particularly good examples originating in England (Cornwall) and the United States (Ohio and Tennessee).

The “Iceland Spar” Calcite variety is named after the country it was originally discovered in and because of its ice-like appearance, although today most “Iceland Spar” actually originates in Mexico. This variety of Calcite best exhibits the double refraction property.

The Calcite variety “Mexico Onyx” should not be confused with the Quartx variety of Onyx, as this is an entirely different mineral alltogether.

Perenially popular, and widely available, the extraordinary number of varieties and occurances ensures that Calcite will likely always be a popular mineral. All Calcite examples are low to moderately priced and therefore available to all.

Common Cuts :
Calcite is most commonly fashioned into decorative ornaments and spheres, but mineral examples are also popular amongst collectors of Calcite, of which there are many. Gem quality Calcite can be cut into almost any known / recognized gemstone shape, although it is normally only faceted for collectors.

Routine Enhancements :
There are no known enhancements for Calcite.

Care & Cleaning :
Calcite is best cleaned using a soft, dry cloth. Extreme heat and all acids should be avoided as Calcite is easily affected, even by relatively weak acids, which cause the stone to effervesce, or bubble. Calcite jewelry should be kept in a fabric-lined box, away from other harder jewelry that could easily scratch this soft mineral.