Coral Stone (Moonga)
Coral (Moonga stone) is an organic gemstone, which is formed by living organisms, unlike most mineral-origin gemstones. Being an ancient gemstone, it has been in use for more than thousands of years. Coral holds a chemical formula of CaCO₃. Owning a hardness of 3 to 4 on the Mohs scale, it has opaque and translucent transparency.