Jadeite and Omphacite are members of a large group of rock-forming minerals called pyroxenes, where Jadeite’s chemical formula is NaAlSi2O6, and Omphacite’s is (Ca,Na)(Mg,Fe2+,Al)Si2O6. Both minerals have different chemistry and/or structure.
A matching colour pair of dark green oval cabochon [SAMPLE A] jade earring were submitted by customer. Spot reading Refractive Index of [SAMPLE A] both show with result of 1.66 which match to Jadeite.
However, result of Raman spectrum show two different result for each side; One side of the article has good match to the result of Jadeite, but the other side match to Omphacite, with the reference library from RRUFF database.
Further tested with FTIR with result similar to RAMAN, this pair of earring mounted with two different type of dark green material; one side is Jadeite, and the other side is Omphacite.
By looking at its appearance, colour, texture, and RI, were absolutely identical to Jadeite. Standard Gemmological testing properties on this test provide overlapped results for Omphacite and Jadeite, without carefully measuring with RAMAN, result will be wrongly identified as jadeite earring.
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