Amethyst is a variety of the silica mineral Quartz and is purple in color. The purple can range from light violet to a deep purple. There are many varieties of Quartz. Citrine which is yellow to orange-brown. Greened Amethyst is Purple Amethyst that has been heated to a specific temperature. The heat sometimes makes the Purple Amethyst change color to green. The stone could also change color to yellow or reddish brown during the heating process. Smoky Quartz is a natural dark brown. Crystal Quartz (Rock Crystal) is clear. Rose Quartz is pink. Milky Quartz is white and it is the most common form of quartz and is found almost anywhere.
Some of the more unusual forms of Quartz are Rutilated Quartz which is clear to yellow with beautiful golden rutile inclusions which are needle shaped. Tourmalated Quartz is clear to milky and has black tourmaline inclusions which are needle shaped.
Amethyst is found all over the world including the United States and Canada. Some of the largest mines are found in Brazil, Uruguay and Zambia. Much of the finest Amethyst comes from Russia. The highest grade amethyst is called Deep Siberian and since it is so rare it is very collectable and commands a higher price. Deep Siberian Amethyst exhibits secondary hues of red and blue.