Natural History - Cut and Polished Quartz Crystal Specimen Group

A Knightia alta fossil fish in matrix. 277 grams, 13 x 9.5 cm



From Wyoming, Green River Formation, U.S.A. Acquired during the 1980s. From the Pradi Collection, Boston, U.S.A.

Seasonally, some 56 million years ago, in the Green River Region of Wyoming, torrential rains fell on the mountains. The rain flowed down the mountain sides, forming wide shallow lakes in the valley below. During the dry season, these lakes evaporated (similar to certain parts of Africa today). Millions of fish died in this short period of time. This climatic cycle happened over a 20-thousand-year period. Layer upon layer of mud was deposited over these years, entombing huge numbers of fish. At a much later date volcanic activity uplifted this area to expose their fossils.

A large Carcharodontosaurus saharicus (African T-rex) tooth with enamel and visible serrations. 13.8 grams, 55 mm



From the Tegana formation of the Sahara Desert, Morocco, North Africa. Acquired during the 1980s. From an old Lincolnshire, UK, collection.

The Carcharodontosaurus saharicus was one of the largest predators of all time (larger than its distant North American T-Rex cousin) and is related to Allosaurus and the South American Giganotosaurus.

A finely formed cluster of flat, hexagonal muscovite crystals; held in a white card tray with label reading: 'MUSCOVITE, Minas Gerias, Brazil'. 33.4 grams, 53 mm



From Brazil. Mineral Imports, London, UK. Gregory, Bottley & Lloyd (Gregory's).