Natural Blue-Green Turquoise. The above Turquoise has its origin in one of the very old, still-working Turquoise mines of West Tibet. Turquoise is the national gemstone of Tibet, and in Tibetan lore is said to have qualities that calm the spirit of the wearer. The Natural Blue-Green of the above two teardrops of Turquoise is a perfect match, cut from the same mother rock, side by side.
Turquoise is one of the two gemstone rocks, the other being the dark blue Lapis Lazuli; it is quite variable in its blue to green colour range, depending on the content of its elements, location to location, from iron to copper to aluminium. The striking, pure sky blue of some Turquoise, as exemplified in the best grades from the now-defunct Sleeping Beauty Mine of Arizona, or from its ancient original source in east Persia, is rarely obtained from the Tibetan mines.
Turquoise is an unstable gemstone for it is porous and its natural colour can be adversely affected, especially, for example, by absorption of the chemicals in cosmetics, perfumes, suntan lotions etc. For that reason the vast bulk of Turquoise out there on the market-place has been treated, often by enhancing the colour and then chemically stabilizing it. The above Natural Blue-Green Turquoise is just that, natural and untreated.
Note: the colour of the above Turquoise is definitely more blue than captured in the images.