Spinel (rare octahedron with trapezohedral modifications!) (ex Kay Robertson Collection)

Item Description

It's not common to find well-formed Spinel crystals from Madagascar on the market these days, but this piece is almost certainly from an older discovery, possibly dating back several decades. The majority of Spinel crystals around the world are octahedral in habit. This particular crystal is a remarkably rare octahedron with trapezohedral modifications on each end! You can see the small four-sided pyramid on several ends of the crystal, though it is not 100% complete, so it's not crystallized all the way around. The color is a dark brownish-black hue (sometimes this material is referred to as Pleonaste) with a bit or rust colored surface oxidation. If you collect crystals based on morphology or if you're a fan of Spinels, do NOT miss out on this excellent, sharp, well-formed example with this incredibly hard to find combination of crystal faces. Ex Kay Robertson Collection (#10408). Kay was a prominent California collector, who specialized in European classics. She nearly lived 100 years from April 1920 - March 2020. See the article in the March-April, 2007 Mineralogical Record ( https://www.mineralogicalrecord.com/pdfs/Kay%20Robertson%20Collection.pdf ), and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017.