Cobaltoan Calcite Crystal Specimen

Description

A richly crystallised pink Cobaltoan Calcite face with small green and dark mineral areas against a pale natural matrix.

This 298 g cabinet specimen presents an expansive face of raspberry-pink Cobaltoan Calcite crystals, with small green mineral patches and contrasting dark areas. The surface is richly textured, mixing tiny sparkling crystal faces with a few larger pink crystals. The pale matrix remains visible at the edges and along the side.

The green and dark associated minerals have not been confirmed by analysis and are described by appearance. The pink colour of Cobaltoan Calcite is associated with cobalt in the Calcite structure. The exact piece offered is shown in the photographs and video.

Locality: Kolwezi Mining District, Lualaba Province, Democratic Republic of the Congo.

Condition and photography: Natural contacts and matrix edges are visible. Please inspect every view for details. Colours can vary with lighting and screen settings. Handle from beneath the matrix and avoid acids.

Calcite is calcium carbonate, a mineral with an unusually wide range of crystal forms. It occurs in sedimentary rocks, mineral veins and many other geological settings. Although the composition remains broadly the same, differences in growth conditions can produce dramatically different outlines, from broad faces to slender or densely grouped crystals. This variety is part of its interest for a mineral collection.

Calcite has well-developed cleavage: it can split along particular planes in its crystal structure. Its natural growth faces and cleavage surfaces therefore deserve careful distinction. Transparent, translucent and more opaque examples all occur. The shape, arrangement and surface character of this piece are more informative than colour alone, especially when comparing specimens from different localities.

The recorded origin is Kolwezi Mining District, Lualaba Province, DR Congo. Within a collection of Calcite specimens, this locality gives the piece a geographical identity alongside its particular crystal habit and natural setting.

The specimen measures 100 × 70 × 40 mm, with a recorded weight of 298 g. The proportions give a useful guide to its place in a display, with the individual crystal arrangement and mineral association remaining the principal points of interest.

Calcite is relatively soft and has pronounced cleavage, so support the stable part of the specimen when moving it. Avoid pressure on thin plates or projecting points. A secure display helps preserve the delicate edges and the arrangement of growth described for this piece.