Calcite
The most common carbonate on Earth, with a double image inside.
- Family
- Calcite
- Formula
- CaCO₃
- Mohs
- 3
- System
- Trigonal
Drag to turn
Science
Calcite forms in more crystal habits than any other mineral and builds most of the world's limestone and shells. Its birefringence is so strong that a clear rhomb shows two images of anything beneath it. Colours are from trace manganese, iron and included minerals; orange calcite from Mexico is the crystal-shop staple.
- Mineral
- Calcite
- Formula
- CaCO₃
- Crystal system
- Trigonal
- Mohs hardness
- 3
- Specific gravity
- 2.71
- Refractive index
- 1.486 to 1.658
- Lustre
- Vitreous
- Colours
- Colourless, Orange, Honey, Green, Blue
Composition
CaCO₃. Made of Calcium, Carbon, Oxygen, with trace Manganese, Iron responsible for colour.
Origin
- MexicoOrange and honey calcite
- IcelandHelgustadir, Iceland spar, historic
- United States
- China
- Brazil
- United Kingdom
Filled dots are primary sources
Rarity
Ubiquitous; it is limestone, marble and chalk. Optical-grade Iceland spar is the scarce form.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Calcite sits at 3 on the Mohs scale. A steel knife will scratch it; it suits pendants and display more than rings.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Solar Plexus
- Sacral
Element
- Fire
Zodiac
- Cancer
Planets
- Moon
- Sun
Properties
- Cleansing
- Energy
- Motivation
- Study
Lore
Erasmus Bartholin described double refraction in Iceland spar in 1669, which led to the discovery of polarised light. Viking sagas' sunstone for navigating under cloud is most plausibly calcite.
In modern practice each colour has a job; orange calcite is the energiser of the sacral chakra.
- Birefringence0.172, among the highest of common minerals.
- FizzEffervesces in dilute acid, the field test for carbonates.