opaque gem การใช้

Like coral and other opaque gems, turquoise is commonly sold at a price according to its physical size in millimetres rather than weight.
In recent times, turquoise has been devalued, like most other opaque gems, by the introduction onto the market of treatments, imitations, and synthetics.
:The second sentence of the lede in our article Turquoise says " " In recent times, turquoise, like most other opaque gems, has been devalued by the introduction of treatments, imitations, and "'synthetics "'onto the market . "-so evidently, there are synthetic stones out there.
Taking the majority view of scholars in regard to the identity of the gems, and including the implication from the Book of Revelation that the " Onyx " at the end of the fourth row was a " Sardonyx ", there are four colours red, green, yellow, and blue each represented by a clear gem ( red Carbuncle, green Heliodor, yellow Chrysolite, blue Amethyst ), an opaque gem ( red Carnelian / red Jasper, green green Jasper, yellow yellow Jasper / yellow Serpentine, blue-Lapis Lazuli ), and a striped gem ( red Sardonyx, green Malachite, yellow pale golden Agate, blue sky-blue Agate ) . these colours roughly correspond to the sensitivities of the retinal ganglia process colour by positioning it within a blue to yellow range, and separately positioning it within a red to green range ).