Part of the Silicate mineral group Topaz has a hardness of 8. This piece of Natural Blue Topaz weighs 259.30 cts and measures 41x31x21mm.NATURAL BLUE TOPAZ 259.30 CTS 41X31X21MMSKU: NTZ#1 $1,300.00 Regular Price$390.00Sale PriceQuantityAdd to CartBuy Now