Calcite

Calcite from Sweetwater Mine, Ellington, Reynolds County, Missouri, USA, measuring 65 × 34 × 33 mm and weighing 74 grams. The specimen shows a pale yellow, elongated specimen whose proportions give it a clear individual character. The specific mine and county attribution make it a locality piece as well as an example of this widely collected carbonate.

Calcite is calcium carbonate, a mineral whose varied occurrences and forms have made it a continuing subject of collector interest. It is associated with many kinds of mineralised environments, including veins and cavities where fluids deposit material over time. The species' familiarity does not diminish the value of locality detail; it makes careful comparison between individual occurrences all the more rewarding.

The 65 mm longest dimension contrasts with widths of roughly half that size, matching the elongated overall impression in the photographs. The Sweetwater Mine attribution gives the specimen a defined source within Missouri. Together, the measurements and locality allow it to be compared thoughtfully with other Calcites, rather than relying on colour as the sole basis for description. This specimen comes from the David Vince Collection. It offers a compact American locality example with a gentle colour and a distinctive overall shape. Those visible qualities, combined with the named mine and preserved provenance, make it an inviting subject for a Calcite group where the individuality of each specimen is allowed to come through.