The world’s largest blue topaz is exposed in the Natural History Museum in London. The stone weighs about 2 kilograms. It is more than 9,000 carats. It has an oval form. This topaz has a rich blue colour. It is also extremely transparent. The topaz doesn’t have any visible defects. This rare specimen was found in Brazil 30 years ago. The topaz has been stored in the strongbox of the explorer Max Ostro. And now his son Mauruzio decided to present this precious stone for public viewing.

There are some collectors, who want to buy this rare mineral. But Ostro’s family is not going to sell it, that’s why they don’t set its price.