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James Catmur

Thanks for the report Gail it is wonderful to see the specimens, it reminds me of my visit and how much fun that was. And that I must do another one with my son (I did promise him)

James

Philippe Russo · Joined: 12 Oct 2011 Posts: 1

I do share the observations and comments of Jesse ( https://www.mineral-forum.com/message-board/viewtopic.php?p=19838#19838 ). Having been working for the past 7 years on the main different tourmalines (liddicoatites) pockets found in Luc Yen, Vietnam, their habit is very similar to the James Sowerby's large fat 17x17.5cm “rubellite” specimen found in 1795 showing extreme tapering and a dark core of 9x6cm . It would be great to analyze the British Museum specimen whether it is elbaite or/and liddicoatite.
The analogy was very striking from the very first Vietnamese specimen (re)-discovered in 2004 showing tapering, and presenting parallel adjacent crystals with prismatic terminations. The largest single specimen weights over 3 kg and is a cluster of crystals. Also the first pocket 'discovered' was at the surface of the pegmatite and showed a similar pale pink color tending to yellowish to Sowerby's specimen, while the subsequent pockets deeper in the pegmatite delivered crystals with a deeper cranberry color.
As Jesse has mentioned, I have also never seen a close habit example from Burma.
The fact that it was was presented to Col. Symes by King of Ava does not necesserely indicated that it was found in the 'Kingdom of Ava' or formerly Siam/Burma. It could have been found long ago in the nearby NE Vietnam and traded to the Burmese (those are my personal thoughts).

Jesse Fisher · Joined: 18 Mar 2009 Posts: 639 Location: San Francisco

Bonjour Phillippe,

Below is a photo of a tourmaline (14 cm tall) from Yen Bai, that I acquired at the Tucson show in 1995. Similar habit but obviously a thin dark green overgrowth on a pink core. As to the exact species, I have been told by one well-known pegmatite researcher that they are liddicoatite, and by another equally well known pegmatite expert that they are elbaite. Unfortunately, I have not seen any definitive studies published on these tourmalines. I suspect that, like many others, these ones have a layered and highly variable internal composition, and should likely be called simply "polychrome tourmaline."

Cheers,
Jesse