black opal

Digging the ground to discover the most expensive treasure on the planet: A country 'hit it rich' because it owns 90% of the world's reserves
This country owns up to 90% of the global reserves. A small bean-sized stone costs up to 255 million VND.
10 most rare and precious stones in the world
Referring to gems, many people think that diamonds are the rarest precious stones in the world. But in fact, there are some types of stones that are more valuable and rare than