As a result, vanadium emeralds purchased as emeralds in the United States are not recognized as such in the United Kingdom and Europe. In the 1960s, the American jewelry industry changed the definition of emerald to include the green vanadium-bearing beryl. This member of the beryl family ranks among the traditional "big four" gems along with diamonds, rubies and sapphires. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency to be considered a top gemstone. However, in the grading of emeralds, clarity is considered a close second. Normally, in the grading of colored gemstones, color is by far the most important criterion. Properties determining value Cut emeraldsĮmeralds, like all colored gemstones, are graded using four basic parameters known as "the four Cs": color, clarity, cut and carat weight. According to Webster's Dictionary the term emerald was first used in the 14th century. The word "emerald" is derived (via Old French: esmeraude and Middle English: emeraude), from Vulgar Latin: esmaralda/ esmaraldus, a variant of Latin smaragdus, which was via Ancient Greek: σμάραγδος (smáragdos "green gem") from a Semitic language. Most emeralds have lots of material trapped inside during the gem's formation, so their toughness (resistance to breakage) is classified as generally poor. Beryl has a hardness of 7.5–8 on the Mohs scale. None (some fracture-filling materials used to improve emerald's clarity do fluoresce, but the stone itself does not)Įmerald is a gemstone and a variety of the mineral beryl (Be 3Al 2(SiO 3) 6) colored green by trace amounts of chromium or sometimes vanadium. Hexagonal (6/m 2/m 2/m) Space group: P6/mсc
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