This is a true rarity–a Montana sapphire over five carats. Any natural sapphire over five carats is quite rare, but sapphires of this size are extremely rare from the deposits in Montana. The crystal was cylindrical, with the long axis of the crystal on a-axis, which in these sapphires is a blue-green color, while the c-axis–on the ends–is blue. Normally I try to cut all of my sapphires on the c-axis for the blue color, but that would have been too wasteful in this case, so I cut it on the long a-axis. Because I cut it on the a axis, the ends of the gem bring in the deep blue color of the c-axis while the center shows the green of the a-axis. The gem shows flashes of deep blue and green-blue as its tilted in the hand and the effect is quite beautiful. I had this sapphire heated in Montana as there was a lot of natural rutile silk in it. The treatment improved the color and clarity of the gem and is permanent and stable.
This sapphire is faceted in a custom radiant rectangle design; the resulting gem is very bright and lively in the hand. While there are a few tiny natural inclusions visible in the macro images, they are too small to see in the hand without a 10x loupe–its an eye clean gemstone. It weighs 5.62 carats and measures 11.7 x 7.4 x 6.4 mm. It would make an amazing center stone for a beautiful engagement ring!