Say lapis lazuli and you wouldn’t be alone thinking of a royal blue colour perhaps with golden flecks, you don’t really recall the patches of white calcite but they’re there, most prized are the uniform rich blue colours with minimal calcite and pyrite.
Most of the Lazpis Lazuli available today is from Afghanistan, there’s a series of mines, mostly known by number ie. mine 1, mine 2, mine3
Although fairly rare you do find lapis lazuli crystals
However the range of colours from these mines can vary, (along with the price).
Often you see rough stone for sale that’s wet to give an indication of how the colour will appear with a polish, however if you’re choosing lapis the local miners blow on the stone to see how the moisture in their breath appears on the stone(inside tip!)