This round ornament set with a central turquoise is fitted with a large silver pin to the reverse and served as a cloak pin or cloak ornament.
Such a fastener would have attached to the front of the dress (kira) to help secure the cloak. Other types known as korma were worn in pairs, but the example here is less common.
The example is in a fine, intact condition and is wearable today as a brooch.
References
Geoffrey-Schneiter, B., Bijoux des Toits du Monde de la Chine au Caucase, Foundation Baur, Musee des Artes D’Extreme-Orient/5 Continents, 2012.
Giehmann, M., Himalayan Treasures: Adornments from Tibet, Nepal, Bhutan, Ladakh & Arunachal Pradesh: The Manfred Giehmann Collection, 2019.
Leurquin, A., A World of Necklaces: Africa, Asia, Oceania, America from the Ghysels Collection, Skira, 2003.
Myers, D., and S. Bean (eds), From the Land of the Thunder Dragon: Textile Arts of Bhutan, Serindia, 1994.