How to identify Pink Cobaltoan Calcite

To correctly identify Pink Cobaltoan Calcite (CaCO3 (Cobaltoan Calcite)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Varies from pale pink to vibrant rose-pink, magenta, or reddish-pink. The color is uniform within individual crystals or masses.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) to sub-vitreous, sometimes pearly on cleavage surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Can be granular, massive, botryoidal (grape-like), mammillary (breast-like), or in distinct rhombohedral crystals. On matrix, it often forms crusts or druzy coatings.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Typically rhombohedral, scalenohedral, or prismatic. Often found as aggregates of small crystals, botryoidal masses, or drusy coatings on matrix.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect rhombohedral cleavage in three directions, producing characteristic rhomb-shaped fragments.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in hydrothermal veins, especially those associated with cobalt-nickel-silver deposits, and in the oxidized zones of polymetallic ore bodies. It often occurs with other cobalt-bearing minerals, various sulfides, quartz, and other carbonates.

Key Facts

Hardness

3 on the Mohs scale

Specific Gravity

2.71 g/cm3 (pure calcite, cobalt substitution slightly increases it)

Crystal System

Trigonal

Color

Pink, rose-pink, magenta, reddish-pink

Luster

Vitreous to sub-vitreous, sometimes pearly

Transparency

Transparent to translucent

Fracture

Conchoidal to uneven

Cleavage

Perfect rhombohedral in three directions at 74°55'

Composition

Calcium carbonate (CaCO3) with significant substitution of cobalt (Co2+) for calcium (Ca2+)

Physical characteristics

• Crystal Habit: Rhombohedral, scalenohedral, prismatic, massive, granular, botryoidal, mammillary, stalactitic, fibrous, lamellar.
• Cleavage Type: Perfect rhombohedral {1011}
• Fracture Type: Conchoidal to uneven
• Tenacity: Brittle
• Luster Type: Vitreous to sub-vitreous, sometimes pearly on cleavage surfaces

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