Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes. It also occurs in low silica igneous syenite and nepheline syenite intrusives. It commonly occurs as a detrital mineral in stream and beach sands because of its hardness and resistance to weathering.
Herein, what is the most rare gemstone?
The following 10 gems are the world's rarest and most valuable gemstones.
- Poudretteite. First discovered in the 1960s in the Poudrette quarry of Mon Saint Hilaire, Quebec, Poudretteite is one of the rarest gems known today.
- Black Opal.
- Red Beryl.
What is the rarest sapphire in the world?
Most Valuable Sapphire Gemstones. You will often hear that the rarest and most expensive sapphire is the pink-orange padparadscha from Sri Lanka. But while the padparadscha is extremely rare, the finest blue sapphires are the ones that receive the top prices at auction.
What is natural corundum?
Corundum is best known for its gem varieties, Ruby and Sapphire. Ruby and Sapphire are scientifically the same mineral, but just differ in color. Ruby is the red variety, and Sapphire is the variety that encompasses all other colors, although the most popular and valued color of Sapphire is blue.
You May Like Also