Cassiterite (cyclic twins) on Quartz

Item Description

Bolivia over the last 125 years has probably produced more tin than any other country in the world. The great tin deposit at Viloco (sometimes called Araca) is not just a source of ore, as it has produced some of the most magnificent Cassiterite specimens extant. This particular specimen hosts excellent, sharp, highly lustrous, black to golden color (when backlit) cyclic twinned crystals associated with prismatic white/colorless Quartz crystals on matrix. The luster and form of the Cassiterite is great for the material. The largest crystal measures 1.4 cm across. These classic specimens from Viloco are simply not seen for sale in today's market very often, especially with such sharp and lustrous crystals like this. Great quality all around, with no real damage that I can see with the naked eye. It's hard to find such fine crystallized Cassiterites on beautiful Quartz matrix like this from Viloco.
From the collection of Gary and Terry Butts of Livermore, Colorado. This husband and wife collecting duo were childhood sweethearts, and have been together since they began dating as teenagers growing up in East Des Moines, Iowa in the 1950s. Both of them had an early interest in the hobby thanks to the fact that Terry's parents had a keen interest in lapidary, which sparked an interest in rocks for both of them. Gary and Terry were featured in an article in the Des Moines Register on Feb 4, 1962 (see photo in this listing) highlighting their interest and prowess in the hobby as youngsters. Gary traveled to various localities around the US as a teenager with his father (who worked in the tin industry), to personally collect specimens. He then attended the School of Mines in Golden, Colorado and graduated in 1967 with a degree in extractive metallurgical engineering. We went to work for Duval Corp at the Esperanza Mine south of Tucson, Arizona and then work for Cyprus Mines, Hazen Research, Pincock, Allen & Holt and the Colorado School of Mines Research Institute. His final job was in the mineral and environmental division of Intertek Testing Services of London, which owned the Canadian mineral testing company, Bonder Clegg. Gary's various jobs allowed him to travel the world and build his collection by buying a lot of specimens in person when they were coming out of the ground. Additionally, Terry's uncle was a miner in Creede, Colorado and later owned a rock shop which supplied Gary with specimens from the area. The specimens in this auction represent what Gary and Terry considered the "cream of the crop" of their collection.