Question: what are the rare gemstones?
Answer: TANZANITE // FOUND ONLY IN TANZANIA. ... , BLACK OPAL // THE DARKER THE BETTER. ... , PARAIBA TOURMALINE // NEON LUSTER. ... , GRANDIDERITE // ONE EXCEPTIONAL EXAMPLE. ... , ALEXANDRITE // COLOR-SHIFTING GEM. ... , BENITOITE // STATE GEM OF CALIFORNIA. ... , PAINITE // ONCE THE WORLD'S RAREST GEM. ... , RED BERYL // TINY AND SCARCE.