What Is It? Labradorite, Ect.

Trade names for rocks and minerals are often misleading, and most of the time, it's unintentional.  Take for instance Labradorite, Spectrolite and Larvikite.  All 3 are feldspars and do have a resemblence.  Labradorite is mined in Labrador Canada.

Spectrolite is mined in Ylämaa Finland.

And Larvikite, from Larvik Norway.

(The first two pictures are mine, the Larvik is from http://www.mindat.org/ , one of the best places on the web to learn about rocks.)

These are all similar rocks, but when you have them in hand, the differences are simple to see.  I can't really explain how Spectrolite feels smoother or Larvikite is heavier to work.  If in doubt, research, research, research.  That's what the internet is for!