John Sinkankas (May 15, 1915 – May 17, 2002) was a Navy officer and aviator, gemologist, gem carver and gem faceter, author of many books and articles on minerals and gemstones, and a bookseller and bibliographer of rare books.
John Sinkankas (May 15, 1915 – May 17, 2002) was a Navy officer and aviator, gemologist, gem carver and gem faceter, author of many books and articles on minerals and gemstones, and a bookseller and bibliographer of rare books. (en)