Garnet not like sapphire blue in subdued daylight but more reminiscent of the grayish blues and greenish blues sometimes seen in spinel. However, in white LED light, the color is equal to the best cornflower blue sapphire, or D block tanzanite; this is due to the blue garnet's ability to absorb the yellow component of the emitted light. Pyrope is an indicator mineral for high-pressure rocks. The garnets from mantle-derived rocks, peridotites, and eclogites commonly contain a pyrope variety. Spessartine or spessartite is manganese aluminium garnet, MnAl(SiO). Its name is derived from Spessart in Bavaria. It occurs most often in granite
Tension ring for forming metal compression-spring gemstone mounting. Patent 5,188,679 is for the actual metal compression-spring gemstone mounting, i.e., the outcome of the method patented by Kretchmer. Tension ring A tension ring is a type of finger ring in which the gemstone is held in place by pressure rather than prongs, a bezel or other mounting. The metal setting is actually spring-loaded to exert pressure onto the gemstone, and tiny etchings/grooves are added to the metal in order to create a shelf for the gemstone's edges to rest. The gemstone appears to be suspended in the air with nothing holding it in