Thus, the term chatoyancy, a word combination involving two French words: chat and oeil.
Looking straight on, it looks just like the slits a cat's eyes form.
This band of light shifts as the stone moves from side to side. This results in a shifting band of light which bisects the stone across the center. When bands of these needle-like crystals, sometimes referred to as "silk," form parallel to the C-axis, gemcutters can maximize this inclusion to create a very special effect called chatoyancy.Ĭhatoyancy occurs when a gemstone with silk parallel to the c-axis is cut in cabochon, with the cuts made perpendicular to the c-axis. Under a microscope it looks like needle-like crystals of a reddish-brown color. The included material, called rutile, is titanium dioxide. While the primary chemical formulation of cats eye chrysoberyl remains aluminate of beryllium, inside the crystal lattice rests an uncommon inclusion. An aluminate of beryllium, chrysoberyl comes in several popular varieties, including alexandrite and cats eye chrysoberyl. In 1789, geologist Abraham Gottlob Werner discovered the semi-precious gemstone chrysoberyl. This handsome vintage mens ring features a stunning 7.6 carat cats eye chrysoberyl. The extensional setting facilitated the formation of Cu- and Au-rich magmas which was derived from enriched mantle and lower crust.Vintage Mens Cats Eye Chrysoberyl Ring 18K Gold. The Yukeng–Banling deposit, the contemporaneous Caomen alkaline granite and Xiaokeng quartz-diorite in the SVB formed under an extensional setting, due to high-angle subduction of the paleo-Pacific plate. Mixing of the Cu- and Au-rich fluids with meteoric water led to precipitation of the Cu–Au veins along NW-trending faults. The isotope data, together with geological, mineralogical and geochronological evidence, favor a primary magmatic source for sulfur and metals in the ore fluids. Co/Ni ratios for stage II pyrites range from 1.42 to 5.10, indicating that the Yukeng–Banling deposit records the past involvement of magmatic hydrothermal fluids. These age-calculated lead isotopic data for alkaline granite are similar to those for the analyzed sulfides. δ 34S values for eight pyrite separates range from − 2.1 to + 4.1‰ with an average of + 1.7‰, and δ 34S values for galena and sphalerite are 2.3‰ and 2.2‰, similar to magmatic sulfur. All samples plot in an area between the magmatic field and the meteoric line, suggesting that the ore-forming fluids are derived from a mixed source of magmatic and meteoric waters. Six ore-related quartz grains have δD H2O values of − 69 to − 43‰, and δ 18O H2O values calculated using total homogenization temperatures that range from − 2.0 to 0.7‰. Microthermometric measurements of fluid inclusions in quartz and sphalerite from stage II veins indicate that the Yukeng–Banling deposit is an epithermal deposit. Zircon U–Pb and Rb–Sr isochron ages indicate that the Cu–Au mineralization is coeval with the Caomen alkaline granite and Xiaokeng quartz-diorite, both emplaced at ca. Native gold is present as veinlets in fractures of fine-grained pyrite from stage II. The mineralization can be divided into three stages (stages I, II and III). Ore-related hydrothermal alteration is well developed on both sides of the veins, dominated by silicification, sericitization, chloritization and argillation with a banded alteration zonation. Ore bodies commonly occur as lodes, lenses and disconnected pods dipping SW with vertical zonation of ore minerals. The Yukeng–Banling deposit is a typical fault-controlled hydrothermal Cu–Au deposit in the Shanmen Volcanic Basin (SVB), SE China.
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