TERRIUM — A mineralogy cabinet


Calcita Cobaltocalcita

Calcita is a mineral with formula CaCO₃ + Co, in the Carbonatos group. This specimen comes from Musonoi, Kolwezi, Lualaba, Alto Katanga, República Democrática del Congo (ex-Zaire) and joined the Terrium collection in 2025.

Calcita Cobaltocalcita from Musonoi, Kolwezi, Lualaba, Alto Katanga, República Democrática del Congo (ex-Zaire) — Terrium

Description

Well-formed geode with rhombohedral crystals of intense fuchsia to violet-pink—the hue collectors call 'cyclamen'—distributed evenly over the interior of a natural cavity. The matrix is massive and light-toned, creating contrast. Sharp crystals, with no powdery residues or visible coatings.

History of this specimen

Although objectively it is a very good reference piece for provenance, colour, definition and cabinet appeal, the piece does not excite me. I do not know what led me to buy it, because it is not sculptural beyond having a small cavity. It makes me reflect so I choose better. It is a learning piece about what moves me and what does not. It also came misidentified, with an erroneous label. A typical specimen from the lots that came out during the years 2020–2022 in Musonoi.

About Calcita

Cobaltoan calcite is a cobalt-rich variety of calcite, valued for its pink to fuchsia colour. It typically forms in hydrothermal environments associated with cobalt and copper sulphides and carbonates.

About the locality

The Musonoi deposit, in the Congolese Copperbelt, is renowned for producing the most intense and bright cobaltoan calcites worldwide. These pieces are from the vein worked between 2010 and 2017, much noted among collectors. They come, as expected, from oxidation zones of copper–cobalt veins within altered dolomites.

Technical data

Catalogue No.
0089
Composition
CaCO₃ + Co
Name
Calcita
Variety
Cobaltocalcita
Group
Carbonatos
Category
Cavella
Matrix
Roca dolomítica gris clara
Mine
Musonoi
District / Municipality
Kolwezi
Province
Lualaba
Region
Alto Katanga
Country
República Democrática del Congo (ex-Zaire)
Size (cm)
7.4 x 5.7 x 4.3
Weight
230 g
Acquired
2025
Etymology
From cobalt, for the dominant element, and calcite, for its belonging to this mineral group.
Quality
Buena
Value trend
Al alza

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