Zircon
Zircon is not a very well-known gemstone, but it is one of the most important gemstones of today. Many people confuse zircon with the artificial diamond simulant, cubic zirconia. Of course, the two are completely different!
Zircon occurs in a wide range of colors including yellow, orange, red, green, blue, violet, brown and combinations in between. Yellow-brown to orange and red zircon are the most common occurrences, along with colorless. Blue is the most popular, but its color is obtained through the heating of brown zircon, usually from Cambodia and Burma.
Due to pleochroism, blue zircon can look greenish from certain angles. Medium dark, pure blue stones have the most value.
Green zircon is very rare and typically very expensive.