The Russian vogue for stone-cutting led to the creation of some of the most beautiful objets d'art, more famously those in malachite. Malachite is a stalagmitic form of copper carbonate, and the technique used in the manufacture of objects and furniture is known as Russian mosaic. The malachite was sawn into very thin slices and then applied to a stone or metal ground, the veins being laid to form pleasing patterns. The whole piece was then highly polished with the joins barely visible. Peterhof is the oldest stone-cutting factory, just a few miles from St. Petersburg, however the huge distances from the mines and quarries meant that it was soon joined by the new imperial factory at Ekaterinburg, in the heart of the Ural Mountains. The third most famous factory was Kolyvan, in western Siberia, which specialised in colossal pieces made from the stones extracted from the Altai Mountains.
There is a coloured drawing for a malachite mosaic cup of the same unusual form, with square top, circular body and socle and square base and resting on gilt-bronze sphinx-supports, designed by I.I. Galberg and made for Prince Alexander Nikolaevich Golitsyn. It is after an original design of 1816 by Carlo Rossi. The Galberg design, dated 1826, was drawn in St. Petersburg and the cup made at the Ekaterinburg lapidary works. Another design, dated 1842, and also drawn in St. Petersburg by Galberg, has the same square form. It was never executed (V.B. Semyonov, Malachite, Sverdlovsk, 1987, vol. I, p. 133, fig. 11 and vol. II, pp. 112 and 124, figs. 10 and 59), whilst a similar vase, made by the Ekaterinburg lapidary works and from the second quarter of the 19th Century, in now on display in the Hermitage (ibid, vol. I, p. 182, fig. 43).
This malachite tazza was given to the 6th Earl and Countess of Dunmore by the Count and Countess Potocki. The Countess of Dunmore (d. 1886) was the daughter of the 11th Earl of Pembroke (1759-1827) and had a Russian mother, Catherine (1783-1856), who was the only daughter of Semyon Romanovich, Count Vorontsov, the Russian Ambassador to London. A Countess 'Alexandrine' Potocki is recorded at a ball attended by Queen Victoria in May 1839.
A related malachite tazza, formerly in the Collection of Charles Butler, Esq., 1 Connaught Place, Hyde Park, was sold in these Rooms, 7 December 1989, lot 69 and another pair was advertised by Mallett in their catalogue for 1998. Interestingly, a further tazza, acquired by George, Prince of Wales, later George IV for Windsor Castle, with mounts added by Messrs. Morel and Seddon in 1828, remains in the Royal Collection (illustrated in H. Roberts, For the King's Pleasure, London, 2001, p.178, fig.205).