Crystals of light blue, blue and greenish-yellow sapphires
, up to 1 cm in size and suitable for cutting, are found in modern alluvial gold-bearing placer deposits of the Nezametny gold mine, in the Big Ussurka River basin, a tributary of the Ussury River, in Primorskiy Kray.
and associated minerals - zircon
), and rutile
- are probably derived from nepheline basalt (ankaratrite), which is part of the Pliocene Shufan formation.
Ref: E.Ya. Kievlenko, Geology of gems, 2003, p. 63