Blue Gray Sapphire Unpolished Natural Crystals measure approximately 3x3mm to 16x6mm in size. The natural crystals are top drilled, each gem remains in its natural state without polish or faceting, the sapphires show a dull luster, gems are a light to medium light blue-grey hue with a few Rubies of a bluish red hue, and gems are an uncommon group of natural Corundum crystals.