Cobaltoan Calcite with Calcite & Manganese Oxides

Description

A broad coating of pink Cobaltoan Calcite crystals over pale Calcite matrix, with small dark manganese oxide accents and sparkling crystal detail.

This Kolwezi specimen carries a broad coating of pink Cobaltoan Calcite across its natural pale matrix. Close viewing reveals numerous small reflective crystals and shallow pockets, with a few darker manganese oxide accents among the pink growth. The side and rear views reveal the thickness and irregular structure of the matrix.

The colour associated with Cobaltoan Calcite comes from cobalt within the Calcite structure. Its pink surface and contrasting pale host make this a distinctive display piece from the Kolwezi Mining District in the Katanga Copperbelt.

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

Condition and photography: Natural surface irregularities and contacts are visible; please inspect all views for condition. The supplied images use a dark background and screen settings can alter the apparent shade of pink. Handle from underneath the matrix and keep away from acids.

The finer crystalline growth described here adds another scale of detail to the specimen. Many small faces contribute to the sparkling surface, while the larger outline establishes its overall form. That combination is worth appreciating beyond the main colour: surface texture, spacing and the distribution of growth all help distinguish this individual piece.

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 80 × 55 × 60 mm, with a recorded weight of 305 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.