THESE ARE QUALITY OPAL DOUBLETS. THEY HAVE A LOT OF FIRE AND ARE READY TO SET IN JEWELLERY.WE CALL IT BLACK AS IT IS MADE FROM CRYSTAL MINED AT OUR OPERATION IN LIGHTNING RIDGE WHICH IS FAMOUS FOR BLACK OPAL..THEY ARE BACKED ON NATURAL BLACK OPAL POTCH. MOST DOUBLETS ARE MADE FROM MATERIAL FROM COOPER PEDY. WE HAVE CUT THIS STONE IN ASIA AS ON THE OPAL FIELD IT COSTS $ 3.00 TO $5.00 JUST TO GET ONE MADE HERE. IT TAKES TWICE AS LONG TO MAKE A DOUBLET AS IT DOES TO CUT A SOLID STONE. .ON THE OPAL FIELD WE USUALLY VALUE A DOUBLET AT APP 10% OF A NATURAL SOLID BLACK OPALS.REDDISH COLOURS ARE THE HARDEST TO FIND.WE ARE OFFERING THEM AT OUR FIELD PRICE SO YOU MAY WIN A BARGIN HERE. WEIGHT: 1.01 CTS APP SIZE 9 X 6 X 2 MM 6 MM =1/4 INCH AUSTRALIAN BUYERS PLEASE NOTE BEFORE YOU BID. ALL BIDS AND SHIPPING/HANDELLING FEES ARE IN US$ DOLLARS.