Cassiterite (twins)

Item Description

The famous Siglo XX Mine (Twentieth Century Mine) was given its name in 1901 upon opening, as it was one of the major Bolivian tin mines to start production at the beginning of the century. Its primary ore has always been tin, though it is known for a variety of phosphates and other species. This piece is a classic example of what is essentially crystallized tin ore, in the form of beautiful, well-formed cyclic twins of dark brown-black Cassiterite measuring up to about 8 mm across, associated with a few scattered gem quality colorless Quartz crystals, and no matrix. The piece is in fine condition, and is one of the better examples we've had to offer from this mine in recent years. Keep in mind that despite the large amount of tin that has come from this locality, good crystallized pieces of Cassiterite are still fairly rare on the market from Siglo XX.
From the collection of Chester ("Chet") S. Lemanski Jr. of Browns Mills, New Jersey (https://www.mindat.org/user-461.html). Collection #3734CL. Chet's collection catalogue states that he acquired this piece in May of 1986 from a "hippy dealer" at the Hackensack Show. Chet was born 1947 in started collecting minerals circa 1957. He worked briefly as a drill runner at the famous Sterling Mine, in Ogdensburg, New Jersey and from 1987 to 1990 he helped convert the mine into a public access mining museum. He has held the role of treasurer, vice president and president of the Franklin-Ogdensburg Mineralogical Society (FOMS), and has been a board member and vice president of the Franklin Mineral Museum. The rare copper arsenate, Lemanskiite was named in his honor in 1999.