Porphyry

Porphyry is an exceptionally hard mineral of varying colour. Commonest are reddish and greenish porphyries with fine inclusions of feldspar, quartz and other minerals.

The famous single-coloured - grey-violet and violet - porphyries of the Altai were found in the valley of the Korgon, a fast-flowing mountain river, that in the 18th century could be reached only on horseback. The blocks of stone from which the vases and candelabra in the Hermitage were made were lowered down the steep banks to the mountain rivers. Each block was bound to the crown of a large tree that was sent down the slope "headfirst" so that the branches acted as a kind of brakes. When the frosts set in, the massive blocks were delivered to the works along the frozen watercourses in what was a tremendous struggle.