What is Labradorite?

What is Labradorite?
Labradorite is part of the feldspar mineral group. The feldspargroup has two different varieties,the orthoclase (alkali) ​feldspars,which include amazonite,orthoclase and moonstone, and
the plagioclase feldspars. The  plagioclase feldspars include labradorite and aventurine feldspar.

Labradorite is a colourful and interesting stone which has a range of colours and optical effects. It is popular with jewellery designers and buyers. It is named after
 the source of the material - Labrador in Canada. It is also found in Mexico,Norway, Russia, and Madagascar. 

Below: - Labradorite pendants from Modern Vintage Style
  
Labradorite has a metallic rainbow effect similar to black opal, except with larger spots of colour. The effect is termed labradorescence. Similar to  moonstone the effect is produced by the interference of light at the junctions of internal structures. The material can be red, yellow, transparent orange and colourless, and may be cut into a  faceted stone. 

Labradorite can also have a semi opaque black - grey to brown - grey body with iridescent flashes of greens, blues, yellows, and oranges that appear when it is moved in the light. This type of material is most sought
after by buyers.

Below: L to R: Madagascan Labradorite, Finish Spectrolite, and
Electic Blue Spectrolite
   

Madagascan labradorite is almost transparent with a pale grey tint. It contains small sparkling inclusions and has lovely colour play in pink, peach, yellow and turquoise.

Finish labradorite is called Spectrolite. It tends to have a dark  opaque colour to the body , with a schiller in pink, orange, blue or yellow. The most prized material has an electric- blue schiller. Spectrolite can also display a cat's - eye effect.