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Burmese amber, or Burmite, is sought after as a gem material and is also well known for hosting a wide variety of interesting invertebrate and plant inclusions. It is mainly recovered from deposits near Tanai (or Danai) in the Hukawng Valley of Kachin State, northern Myanmar, where several different amber varieties are found (e.g. Jiang et al. 2020). Other Burmese amber localities, which were discovered more recently, include Hti Lin (Tilin) in the Magway Region of western central Myanmar, and Pat-tar Bum (Pat-ta Bum) near Khamti (Hkamti) in the Sagaing Region of northern Myanmar.
The Pat-tar Bum deposits were initially mined during the British colonial period, but were abandoned in the 19th century and reopened in 2010. Due to an increase in amber demand from mainland China, mining activities increased at Pat-tar Bum in 2012–2013. This amber was briefly described by Liu (2018), and in January 2018 some of the present authors (TTN, CC and NBBK) visited several sites in the Pat-tar Bum area. Initial results of the authors’ research were briefly presented by Thet Tin Nyunt et al. (2019), and this article provides more details on the geology, mining and gemmological properties of this amber (e.g. Figure 1).
[Figure omitted: See PDF.]
[Figure omitted: See PDF.]
[Figure omitted: See PDF.]
Location and Geology
The Pat-tar Bum amber deposit is located near Nampilin stream about 40 km south-east of the town of Khamti (25º41′ N, 95º50′ E; Figure 2) and about 11 2 km southwest of Tanai. The specific sites visited by some of the authors include Lachun (also spelled Laychun and Lachon) Maw, which was the most productive mining area, as well as Kyat Maw, Shan Maw, Gyar (also spelled Kyar) Maw and Kyauk Tan Maw (Figure 3). (‘Maw’ means ‘mine’ in Burmese.)
The Khamti area is mostly underlain by Paleocene to Eocene molasse-type sedimentary units of the Paunggyi Formation. Cretaceous units are locally present, including the Kalaw Red Beds, the Kabaw Formation and other marine units including limestone; also occurring in the area are ultramafic and mafic intrusions of mostly Jurassic age (Soe Thura Tun et al. 2014). The intrusions are mainly represented by peridotite and serpentinite, and commercially important jadeite deposits are locally associated with the latter rock type...