This is the most expensive pearl in the world, priced at 137.5 million dollars. It is 5 ft. high and weights 6 ton. It was unearthed in Mongolia . The pearl was formed out of fluorite mineral, it tends to glow in the dark.
18 ton Nephrite Jade boulder found in Canada in 2000.
A 20-ton jade boulder found at the Polar Jade mine near Dease Lake in northwestern BC
There are two categories of opals - common and precious. The Precious opals are composed of three groups: white, black, and fire opal.