This gem was faceted from an unheated piece of tanzanite–most tanzanite has been heated to remove the greenish-yellow component to make the gem a dark blue to purple-blue. In these images you can see the pleochroic nature of the gemstone if you know what to look for–some of the facets are showing a more violet-blue while others show a more teal blue and others a medium light blue. Natural blue-purple tanzanite like this was heated underground over the millennia and retains a trichroic appearance–showing various shades of blue, green/yellow and violet/red. Heating removes the yellow component, leaving behind the red and blue, creating a deep blue to blue-purple gem.
The gem is 1.04 carats and measures 6.68 x 3.88 mm. It’s cut in a classic round brilliant design and would make a great center stone for a ring.