Kaolinite pseudomorph after Carlsbad Twinned Orthoclase (''floater'' specimen) (ex Al Kidwell Collection)

Item Description

These are some of the most iconic pseudomorphs in the world, and true classics from Cornwall. This excellent specimen is a great example of the beautiful "floater" crystals of Carlsbad-twinned Orthoclase which have been pseudomorphed by Kaolinite from the Hensbarrow Moor in St. Austell in Cornwall. What really sets this piece apart from others is the fact that it's not just a solitary twin, but TWO twins intergrown, which is exceedingly rare in my experience with this material. The piece is complete all the way around, and has retained its sharp original crystal form with a beautiful egg-shell white color. Minor roughness in a couple spots, but still very good quality. Great old classic material from Cornwall. I'm told that these are called "pig's eggs" for whatever reason. Valued at $1,500. From the worldwide mineral collection of Albert (Al) Lewis Kidwell (January 1, 1919 - August 16, 2008). Al was a well-known mineral collector and research geologist with Carter Oil Company and later Exxon Oil Company in Houston, Texas. The phosphate species Kidwellite was named in his honor in 1974.