||The gemstone jade, is actually two different minerals that look very similar and have similar physical properties. It was used in prehistoric times for buttons, beads, and tubes. It was also used in axe heads, knives, and other tools.
Jade has been in use in China since neolithic times. It has been used in tools and art for more than 5000 years. Jade is the toughest gem stone (not the hardest), it is made up of interlocking fibers that create a material able to withstand high pressure without fracturing. Hence it was even used in anvils for metal work. A small piece of jade can be struck with a hammer and will deform, then spring back to its original shape. (Not a recommended test!)
Jadeite is the far more rare variety and comes in virtually all colors. Blue, lavender, red, green, pink, yellow, white and black. The bright translucent green is considered the best, and sometimes called "apple green". The rarest and often most expensive is the translucent red jade. Today the best sources are Burma and Guatemala.
Nephrite comes in far fewer colors, green, white and black the predominant ones. It is far less rare and found in many locales. Large deposits exist in the north america, especially Canada, Alaska, California, and Wyoming. The white variety often has translucent and nearly transparent areas mottled throughout and is sometimes called "mutton-fat" jade.
Because it has a tough nature, it can be carved into intricate shapes and is not prone to breakage. Hence small pendants and amulets with very fine detail are often available.
A relatively new material that is "jade", meaning it is made up of several jade constituents is called "Maw-sit-it". It has both jadeite and nephrite in the same rock, but its true claim to fame is that it contains chromium and thus produces bright and lively shades of green different than the typical jades. It is extremely rare and exits in only one locale to date. (Burma - Myanmar)