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Natural Emerald 4mm round 0.2ct faceted A gemstone Natural Emerald - for Gemstone collectors, for Jewellery designers or for Mystic and positive energy as an amulet Colour: Medium to light green Clarity: Included Treatment: Oiled Gold ring (wedding band) not included and shown for size comparing only. Emerald Mohs hardness 7.5-8, Specific gravity 2.68-2.78, Refractive index 1.560-1.602. Emeralds are a green member of the Beryl clan, coloured green by trace amounts of chromium and sometimes vanadium. Most emeralds are highly included, so their toughness and resistance to breakage is classified as generally poor. The word Emerald is derived from Old French: Esmeraude and Middle English: Emeraude, and from Latin: Esmaralda/Esmaraldus, a variant of Latin Smaragdus, which originated in Greek: (smaragdos; "green gem"); its original source being either the Hebrew word izmargad meaning "emerald" or "green" or the Sanskrit word marakata meaning "green." The name could also be related to the Semitic word baraq ("lightning" or "shine") (cf. Hebrew: bareqeth and Arabic: barq "lightning"). It is the same source for the names Persian (zomorrod), Turkish (zümrüt), Sanskrit (maragdam), Russian (izumrud) and Armenian zmruxt. Emeralds, like all coloured gemstones, are graded using four basic parameters, the four Cs of Connoisseurship; Colour, Cut, Clarity and Crystal. The last C, crystal is simply used as a synonym that begins with C for transparency or what gemmologists call diaphaneity. Before the 20th century, jewellers used the term water as in "a gem of the finest water" to express the combination of two qualities, colour and crystal. Normally, in the grading of coloured gemstones, colour is by far the most important criteria. However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue, but also a high degree of transparency to be considered a top gem. Colour is divided into three components: hue, saturation and tone. Yellow and blue, the hues found adjacent to green on the spectral colour wheel, are the normal secondary hues found in emerald. Emeralds occur in hues ranging from yellow-green to blue-green. The primary hue must, of course, be green. Only gems that are medium to dark in tone are considered emerald. Light-toned gems are known by the species name, green beryl. In addition, the hue must be bright and vivid. |