Polished Green Opal slab GRN90 prehnite Dimensions at widest points approximately

Dimensions at widest points approximately 95 mm x 95 mm x 75 mm thick

Oldest agates on Earth

Dimensions at widest point approximately 130 mm x 110 mm x 8 mm

RB246 Lepidolite

Weight is 380 grams

Polished Green Opal slab GRN90 prehnite Dimensions at widest points approximatelyGRN90 Green Opal & Magnesite slab, cut and polished on one side . Dimensions at widest points approximately 200 mm x 100 mm x 16 mm thick Weighs 442 grams Green Opal occurs at a location south of Kalgoorlie in the Eastern Goldfields of Western Australia. The green colouration is caused by traces of nickel and or chromium. Sometimes it exhibits striking contrasting veins of magnesite.