Romania Registered cover with Mineral stamps 2010

Registered cover received from Silviu Thank you! The set is issued in 2010, depicting Quartz Calcite (50B), Free Gold, Quartz (1.40L), Rhodochrosite (1.60L), Calcite (2.40L)  and Red Barite (7.60L).

Romania Prepaid Cover 2010

Prepaid Cover issued in 2010, Romania, depicts Crystal Cluster on the left, and the pre-printed stamp depicts Amethyst with denomination of 1L

Romania 1985 set of 6 stamps

The issue depicts Quartz and Calcite (50B), Native Copper (1L), Gypsum (2L), Quartz (3L), Stibnite (4L) and Tetrahedrite (5L).

Gypsum is a mineral composed of Calcium and Sulphur.
Stibnite is composed mainly by Sulphur.
Tetrahedrite is a mineral with Composition of Iron and Zinc, with some Silver, Copper and Mercury.