Dioptase Crystal Mineral Display Specimen

A colossal cut section of cream-coloured stalagmite showing natural ripples. 66.7 kg, 90 cm



Previously from a Hong Kong collection. Ex property of a London, UK, gentleman, 1990s.

A stalagmite, is an upward-growing mound of mineral deposits growing on the floor of a cave due to accumulation of material deposited from ceiling drippings. They are typically formed by the deposition of calcium carbonate and other minerals, which is precipitated from mineralised water solutions. Limestone is the chief form of calcium carbonate rock which is dissolved by water that contains carbon dioxide, forming a calcium bicarbonate solution in underground caverns.

On a rectangular matrix, showing good detail especially on the fins. 297 grams, 10.7 cm



From Wyoming (Green River Formation), USA. From the private collection of Kenneth Machin (1936-2020), Buckinghamshire, UK; his collection of antiquities and natural history was formed since 1948; thence by descent.

In southwest Wyoming (and parts of Colorado and Utah) in the Green River Formation are found some of the world's most outstanding specimens of fossil fish. The Green River system was composed of three lakes: Lake Ulinta, Lake Gosiute and Fossil Lake. These Eocene lakes lay in a series of intermountain basins formed by geological events that uplifted the Rocky Mountains during the early Tertiary time. The climate was much different from the desert-like climate of this area today. Both the fauna (crocodiles, alligators, boa constrictors and some subtropical fish families) and the flora (such as large palm trees) indicate a climate much like that found along the Gulf Coast today. Large amounts of ash found in the sediments indicate that volcanoes were particularly active at this time.

Rounded mass of Holocystis elegans on a matrix with a brachiopod and wormholes, free-standing. 250 grams, 79 mm



Found Lower Greensand, Atherfield, Isle of Wight, Hampshire, UK. From the private collection of a Leicestershire, UK, gentleman.