Today I offer you, directly from my personal collection There are only 15/20 specimens in the world. Usually the average weight of these opals varies from 5 to 70 ct, this piece weighs 828 ct, therefore 165.6 grams of Indonesian black opal, a true monster. A great peculiarity is its beautiful branch. The value of these opals is usually calculated per carat, small pieces are worth from 1 euro to 5 euros per carat. Today on offer with reserve price at a special price. these pieces come from the petrified forests of Banten, Indonesia, in some rare cases, the opal which is born as liquid silica, infiltrates inside and outside the branches, so after millions of years an opalized fossil is born, a rarity , a true jewel of nature These pieces are found, cleaned of impurities and then a light resin is applied to preserve the piece, because it is of volcanic origin. It is recommended to clean with a cloth with a little oil once a year Museum Piece Top Quality Beautiful color Natural Black Opal Indonesian, Banten Wood Fossil volcanic origin Miocene, Aquitanian ( 22 million years ago ) The piece is opalized on 1 side Multicolor, Flash fire 2640 cts - 528 grams 230 x 90 x 50 mm the piece for sale is what you see in photos! please be careful with the description and measures Shipping via express courier #ExclusiveCabinetofCuriosities