Fluorescent “Poker Chip” Calcite

Description

White, overlapping crystal plates rise around a recessed centre, with a violet appearance shown in the accompanying UV photograph.

From the Liancheng Manganese Deposit in Fujian Province, this Calcite specimen displays overlapping white, tabular crystals in the distinctive “poker chip” habit. Broad plates on one side give way to closely layered growth around an open recess, creating a different view as the specimen is turned.

The fourth photograph shows the specimen under ultraviolet light, where it appears violet. The precise colour and brightness can vary with the UV wavelength, camera and viewing conditions.

It weighs 470 g and measures 140 × 90 × 45 mm. Please examine the six photographs for its crystal edges, surfaces and matrix; the exact piece shown will be supplied.

The tabular growth gives this Calcite a layered appearance. Broad faces establish the shape, while the repeated edges draw attention to smaller stages within the crystal groups. “Poker chip” is a descriptive habit name rather than a separate mineral species. It is this arrangement of plates, rather than colour alone, that makes the specimen distinctive.

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 Liancheng Manganese Deposit, Liancheng County, Longyan, Fujian Province, China. 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 140 × 90 × 45 mm, with a recorded weight of 470 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.