The extremely rare mineral is borosilicate ... The most expensive paraiba tourmaline is a pair of earrings. One weighed 7.46 carats, and the other 6.81 carats, and they sold for about $2.78 ...
In September a cushion-shaped 5.44-carat Paraiba tourmaline ring flew past its US$60,000 upper estimate in auction at Bonhams New York to sell for US$533,900. This is bidding territory more ...