Vintage 925 sterling silver exotic (Tibetan ?) necklace w turquoise and coral

Vintage exotic sterling silver necklace. The pendant has blue turquoise and red coral stones. I also have matching earrings, which are listed separately. Stamped 925 on the pendant and in two places on the 18" long chain. The pendant is 2.8 cm long (with bail). Not sure if the stones are natural or manmade. Please see closeup pictures for details. The metal has some tarnish, which I don't want to clean because it looks like part of the design and adds to the overall appeal.