Cut and Polished Agate Crystal Geode Half Collection [6]

A cut and polished section of fossilised tree. 1.26 kg, 11.5 cm

Fine condition.

From the Isle of Portland, Dorset, UK. Acquired 1950s-1960s. From an old Bristol paleontological collection.

At the base of the Purbeck Formation in Dorset is a layer of rock containing fossil trees that have now been silicified. The trees grew around a saline lagoon that occupied this area towards the end of the Jurassic period. The dominant tree was a large conifer that was adapted to living in what was then a climate of hot, arid summers and warm, wet winters. The growth rings in the wood indicate that a highly seasonal environment prevailed in Southern England during the late Jurassic period. The trees were drowned by the rising waters of the lagoon and many have been preserved in their original positions of growth. At this time Dorset was situated at the same latitude as present-day Malta.

A trio of rounded geode halves, each with a large exposed internal crystal-filled cavity, one with a large single clear crystal. 662 grams total, 74-83 mm



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

Comprising irregular pieces of polished amethyst. 297 grams total, 15-62 mm



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