ALEXANDRITE-DIAMOND-RING
Russia; ca. 1840.

585/- rose and yellow gold; silver-plated; total weight: 13;3g. EU-RM: 66. Ring top D.ca. 3;0 x 2;4cm. 54 diamonds in old- and rose-cut in total ca. 2;0ct TCr(I) SI1-2; 1 faceted alexandrite in cross-cut ca. 1;7ct.
Russian inscription on the rail: Emperor Nikolai Adjutanto Summer 1844 (...).

The gemstone; which was first found in the Urals in 1830; was given its name after the later czar Alexander III. It is green in daylight; in artificial light it is red. The former deposits in the Urals have run out and today there are deposits in Sri Lanka; Brazil; Tanzania; and the US.
Art trade; Van Ham.