The discovery of new minerals always adds colours to the coloured gemstone sector. Johnkoivulaite from Myanmar comes as the latest known species that excites the gemmological community.
The 1.16-carat stone was found in the Pein Pyit mining area of Mogok in Myanmar, according to the Gemological Institute of America (GIA). It was named in honour of John Koivula, a veteran GIA gemmologist and researcher for over 40 years.
After uncovered, the stone was obtained by a gem dealer from Mogok Nay Myao who sent the sample to GIA for identification. The unique gemmological properties of the unusual stone impelled GIA to buy it from the dealer in order to perform additional advanced testing and keep it in the GIA museum which is required by the International Mineralogical Association (IMA) before a new mineral is described. IMA formally accepted Johnkoivulaite as a new gem mineral species in September 2019.
In collaboration with researchers at the California Institute of Technology, GIA performed single-crystal X-ray diffraction (XRD) analysis which indicated a hexagonal crystal structure that was very similar to beryl and other members of the beryl group such as pezzottaite, said GIA. Johnkoivulaite’s membership in the beryl family was confirmed after chemical analysis by LA-ICP-MS and EPMA identified enrichment in cesium, boron and magnesium.
“Standard gemmological testing gave an RI of 1.608, with a birefringence too small to accurately measure, an SG of 3.01, a hardness of 7½, a conchoidal fracture, vitreous lustre, and no reaction to long-wave or short-wave UV. This mineral is especially unique due to the strong pleochroism it shows from deep violet to nearly colourless when observed with polarized light,” said the institute.
“We are privileged to be able to name this mineral after John Koivula who has contributed so much to science and the gem and jewellery industry as a prominent gemmologist and innovator in photomicrography,” said Tom Moses, executive vice president and chief laboratory and research officer. (Photo courtesy: GIA)
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