Sapphire is part of the corundum family; the same family as rubies, and comes in an extensive ranges of colours, with blue and pink commanding the highest prices. In terms of blue sapphires, the colour will depend on the country of origin. The sapphires I currently carry are from Thailand, and they are a nice clear shade of blue, not too dark and inky, no grey or green cast. There has been considerable controversy surrounding some of the treatments that sapphires are put to; for example diffusion treatment and beryllium treatment, and recently, glass-filling. I make a policy of not stocking such stones. The stones I carry have been heat treated, and this is viewed as an acceptable treatment.