Ever-popular turquoise comes in a variety of colours and qualities, from the finest, clearest Persian blue, to green and filled with matrix. Actually some matrix increases value - the regular patterning of the spider's web variety, for instance. Today the finest material comes from China, but the majority of the rest is from the US. I stock US material, and as is common for turquoise, it is stabilised. I have this currently in a choice of round cabochons and rose cuts.