This is something we have not seen before. Brand new on the market. The Mesmera rhinestones feature a new Color Shift Technology.  Developed by Preciosa with the Czech Academy of Science the stones contain a rare mineral that causes the color shift.  As a result, like a mood ring, the stones change colors under different light conditions. The color changes from purple, to green, to pale blue.  See the photo.  
Maxima Flat Back Rhinestones are the latest most upscale premium crystals from Preciosa®. The patented faultless precision machine cut (15 to 18 facets) crystals feature perfect geometry.  They are optimized to allow maximum dispersion of light.  With a unique combination of larger and smaller facets, reflecting 264 unique rays of light, the Maxima crystals create beautiful shimmering effects – the highest available on the market.