Natural Tibetan Green Turquoise, origin one of the Turquoise mines of West Tibet. Handcut side by side from the same mother rock and consequently very well matched in colour and in the speckled matrix of the mother rock.
Note: the green of the above Natural Tibetan Turquoise is in reality a noticeably lighter green than captured in the images; sometimes for this very amateur photographer colours can be problematical, especially with greens and deeper blues, as in Lapis or Sapphire.
Most Turquoise on the market-place these days is treated. The treatment techniques were perfected in the States in the early 1900s when 1. its market for indigenous Turquoise began to grow, and 2. it became quickly evident that Turquoise, because of its porosity, was unstable in its colour, which could be quite adversely affected by the chemicals in certain mass-produced consumer goods like perfumes. The treatment usually involves colour enhancement and stabilization.
The above Natural Tibetan Green Turquoise is just that, natural and untreated. Turquoise will, no matter how carefully it is handled, change colour over time, but if it is handled with care the change will be very gradual and, indeed, the change will not detract from its original attractiveness.
Note: one of the images above shows the reverse side of one of the teardrop Turquoise.