Cobaltoan Calcite with Metallic Sulphides

Description

Sparkling raspberry-pink Cobaltoan Calcite crystals fill a natural cavity, with scattered dark metallic grains providing contrast across the pale matrix.

This 146 g cabinet specimen features lustrous raspberry-pink Cobaltoan Calcite crystals grouped within a natural cavity. Rounded crystal aggregates give the centre depth and sparkle, while the pale outer matrix frames the colour. Small metallic-looking grains are scattered through the surrounding rock.

The associated metallic material is described broadly as sulphides, without assigning a specific mineral species from photographs alone. Cobaltoan Calcite takes its pink colour from cobalt within the Calcite structure. The exact specimen pictured and filmed is the piece offered.

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

Condition and photography: Please inspect every view for natural contacts and surface detail. Colours can vary with lighting and screen settings. Handle from beneath the matrix and avoid acids.

The open areas described in this piece contribute to its depth. Rather than a continuous flat surface, the growth can be followed around recesses and across changes in level. These spaces help distinguish the larger outline from the finer crystalline texture and give the specimen detail that can be appreciated as part of its three-dimensional form.

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 92 × 70 × 60 mm, with a recorded weight of 146 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.