Cobaltocalcite

Calcite

By Tim Matthews, JD, FGA, GG, DGA,
CEO and President of JTV (retired)
Published: June 2014
Modified: December 2021
Cobaltocalcite Polished Cobaltocalcite Rough Cobaltocalcite Jewelry

Cobaltocalcite refers to a stunning pink-red to slightly purplish-red cobalt-rich calcite mineral. Another name for this stone is cobaltoan calcite. Crystals often form as drusy masses and when faceted, gems are rarely seen in sizes greater than 2 carats but can be exceed 8 carats. Gem quality stones come from Spain and the Democratic Republic of Congo. Notable specimens come from the Bou Azzer Mine, Morocco and the Mashamba West Mine and Mindingi Mine, Democratic Republic of Congo.

General Information

Common Name
Cobaltocalcite
Species
Calcite
Transparency
Transparent - Translucent
Dispersion
Strength: Strong Fire
Refractive Index
Over The Limit 1.490-1.885
Birefringence
0.285
Optic Character
Uniaxial
Optic Sign
Negative
Polariscope Reaction
Doubly Refractive (DR)
Fluorescence
SWUV: inert, strong red to weak pink
LWUV: Weak purplish pink to moderate orangy pink
Pleochroism
Dichroic, violet red to rose red
Hardness
3-4
Specific Gravity
2.680-2.740
Toughness
Poor
Inclusions
Irregular bands of white fibrous inclusions that might form and mosaic pattern or white particles that have a banded appearance.
Stability
Brittle
Fracture
Subconchoidal
Cleavage
Perfect, in three directions
Chemical Formula
CoCO3
Crystal System
Trigonal
Chemistry Classification
Carbonate

Cobaltocalcite Colors

  • Pink Cobaltocalcite
    Pink
  • Pink Cobaltocalcite
    Pink
  • Purple Cobaltocalcite
    Purple
  • Red Cobaltocalcite
    Red

Alternate Names

Spherocobaltite, Aphrodite Stone

Countries of Origin

Russian Federation; Angola; Romania; United States of America; United Kingdom of Great Britain and Northern Ireland; Switzerland; Congo; India; Spain; Canada; Sweden; Morocco; Unknown; Italy; Mexico; Slovakia; Australia; France; Peru; Germany

Care

Cobaltocalcite is very soft, so be mindful of scratching. It is easily attacked and dissolved by acids such as vinegar. Avoid abrasives, ultrasonic, solvents and heat. Cobaltocalcite is generally unsuitable for jewelry.