A pair of Restauration ormolu-mounted, pietra dura and malachite plinths circa 1820-30

each with a rectangular molded frieze above a rectangular plinth with concave corners fitted with pendant ribbon-tied husks, the pietre dura-decorated front incorporating an onyx vase with a tulips, roses, daffodils, magnolia and other flowers, the sides and the reverse with malachite panels, above a stepped ormolu base.  One corner mount replaced; originally the plinths for a vases or candelabra.

Collection of the Cholmondeley Family and Sir Philip Sassoon, Bt., at Houghton, sold, Christie's, London, December 8, 1994, lot 55

The tops with a covered hole where a screw pole would have sprung, showing evidence of a previous upper section. Rubbbing and losses of gilding to the top, with no gilding to the top, possibly because it was never meant to have been gilt. General marks and surface abrasions to the top, sides an corners. With one corner shute mount replaced. Rubbing to the gilding on the side mounts with significant traces of verdigris. Minor lossses and small holes to the lower sections of the right sided malachite veneered panels on each of the plinths. Further rubbing and verdigris to the ormolu base. In otherwise good condition.
In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective qualified opinion.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING CONDITION OF A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF SALE PRINTED IN THE CATALOGUE.

These plinths served as the bases for objects such as vases or candelabra and their overall execution and appearance is very characteristic of the taste associated with the great collector and immensely rich Nicolas Demidoff (d. 1828). 

As early as 1806 Demidoff had commissioned the Parisian goldsmith Henri August to supply a guéridon; in 1819 he ordered Pierre Philippe Thomire to supply mounts for a massive malachite vase (now in The Metropolitan Museum of Art, New York), as well as a console table with legs in the form of Nike.  This table was a gift to Grand Duke Leopoldo II of Florence and is now in the Pitti Palace.  Demidoff settled in Florence in 1822 and was Russian minister to the Tuscan Court.  Elevated to the rank of Count of San Donato by the Grand Duke, Demidoff built a magnificent villa at San Donato on the site of lands formerly owned by the Medici.  The villa was inherited by Anatole, his son, Prince of San Donato (1812-1870) and there are records which confirm transactions he had with the Opificio delle Pietre Dure.  It is of interest to note that related items appear in the San Donato sale catalogue, March 15, 1880, in particular lot 311:

311 Quatre Grands et Tres Beaux Vases Medicis en malachite, ornés de bas-relief, de couronnes de pampres et d'anses en bronze doré, reposant sur des socles carrés offrant sur chaque face un médaillon hexagone à bouquet de fleurs en ancienne mosaïque florentine en relief.  Ils sont élevés sur des bases carrées en malachite ornées de même manière.  Les bronzes ont été executés par Feuchère.

A similar plinth is in the Gilbert collection, illustrated, A. González-Palacios et al., The Art of Mosaics, Selections from the Gilbert Collection, Los Angeles, 1982, rev. edn. no. 25.  A related pair of malachite plinths supporting candelabra are illustrated in V.B. Seyonor, Malachite, Sverdlovsk, 1987, 1, fig. 70.