Sanidine

Feldspar is a mineral not usually known for fine collector gem crystals, but at this locality in Madagascar, amazing water clear crystals are sometimes found. This is a terminated gem crystal in excellent condition, crystallized al around. The crystal has a good yellow coloration and is internally transparent, clear enough to facet gemstones. The faces alternate from smooth and glassy to a curvy surface texture that is common to these and always reminds me of a topographic map. Weighs 21.46 grams.  I value this at about $500, though they are scarse - I only saw one at the 2020 Tucson show with a dealer who had a $900 price tag on it, similar size and quality.