THIS IS NATURAL WHITE OPAL MATRIX FOUND IN ANDAMOOKA SOUTH AUSTRALIA.IT HAS BEEN TREATED TO LOOK LIKE EXPENSIVE BLACK OPAL. THE TREATMENT IS PERMENANT BUT IF YOU RE SHAP OR CUT IT YOU WILL HAVE TO RE TREAT IT.THE COLOURS AND FIRE ARE AMAZING.ON THE FIELD THEY CALL THIS CONCRET WHICH IS A HORRIBLE NAME FOR SUCH A BEAUTIFUL STONE..WE DO OFFER GEM MATRIX ON THIS SITE WHICH YOU CAN GET A NATURAL POLISH ON IT-THAT SELLS FOR $10 -20 PER CARAT WHILE THIS SELLS FOR $1-2 PER CARAT FOR LARGER STONES.ITIS ADAZZALING SPECIMEN. THIS SPECIMEN HAS HAD LIQUID GLASS ON THE SURFACE.PHOTO OF THE BACK SHOWING BLUE COLOUR.