When the color changes on tourmaline crystals looking down the C axis it's called Pleochroism.

ple·o·chro·ic

/ˌplēəˈkrōik/

adjective

1. (of a crystal) absorbing different wavelengths of light differently depending on the direction of incidence of the rays or their plane of polarization, often resulting in the appearance of different colors according to the direction of view.
   Some very rare tourmalines are completely open c axis showing no change in color as the stone is rotated.
   As well with pleochroic tourmalines the table top facet should be parallel with the C axis. Preferably with the c axis parallel with the length of the stone. It makes for a nicer looking stone.

2. DRC Congo the premier tourmaline source today. Producing some of the highest quality tourmaline even eclipsing the once considered best of the best Afghan material! I tried to get full high definition close up shots and video to hide nothing as there is nothing to hide.
   
   The video and photos are highly magnified.  It's like looking through a magnifying glass as is so you can see.
   
   This is an excellent master cut stone.  No window cutting.  Master cut should not have gaping window cutting.  GIA sets standards for cutting so gemstones show good reflection.  This stone is cut within those standards for gem quality cutting.  After color cut is the most important of the 4 C's.
   
   When cutting for reflection it takes away a lot of extra weight. Bloated pavilions and shallow cuts add additional weight people end up paying big money for. These stones I have master cut stripped all that extra weight most others leave on so they can charge you for it and make maximum dollar. Most people do not realize this and buy a stone that is not cut to gem quality. When you buy a master cut gem from me your getting value for your dollar. Not only are my prices especially fair the stones are especially high quality.
    
   This stone is loupe clean or close. I didn't notice anything under quick examination with the loupe. The video and photos are highly magnified.  It's like looking through a magnifying glass as is so you can see.
   
   Most of the DRC tourmalines are loupe clean or close. I don't like to exaggerate anything. I've seen so much the spectacular becomes ordinary, so when you pick a stone from me expect it to be the highest quality. I only want to sell perfect stones.  
   
   10% discount for bank wire transfer over PayPal.  Please ask for Business account information.