Lot 1143W. Exceptional Amethyst Geode with Calcite Stalactite, Minas, Brazil. Weighing approximately 225 lbs (102 kgs). Measuring 26 x 21 x 13in. Sold for US$ 20,000 (€17,861). Photo: Bonhams.

A view into an interior world of associated minerals, this is a large and exceptional amethyst geode is worthy of display in the most serious mineral collection. Careful lighting will best reveal the beauty of the calcite stalactite and vivid violet-purple hued amethyst crystals which line the interior. Such spectacular geodes are rarely seen intact in the market and they are remarkable in providing a wondrous view of various stages of mineral growth over the millennia. 

Bonhams. AUCTION 23397: LAPIDARY WORKS OF ART, GEMSTONES, MINERALS AND NATURAL HISTORY - LOS ANGELES