Benitoite
Benitoite is one of the rarest gemstones that is relatively new. It’s a blue barium titanium silicate mineral that fluoresces under UV light. Also, it is an exquisite and most valuable gemstone. Due to its rarity, it can be extremely expensive. In addition, Benitoite rarely exceeds 2 karats.
Poudretteite
Poudretteite is an extremely rare gemstone. It has a hexagonal shape and a very pale pink color. Its price is a whopping $3,000 per karat.
