A garnet and diamond ring, early 19th century

the central cushion-cut stone within a rose-cut diamond-set border and openwork scroll frame, the outer border of large circular-cut diamonds, the shank engraved: 'The Emperor Nicholas to Alan Stevenson 1839', together with a leather ring box embossed with the Imperial eagle, and letter

According to the 1957 letter accompanying this lot, the ring was given by the Emperor to Alan Stevenson (1807-1865), the famed Scottish lighthouse engineer, following "the completion of the light house construction carried out by him in the year 1830.  It is understood that to show his appreciation the Emperor drew the ring from his little finger and presented it with a grandiose flourish." 

Thence by descent

Excerpt from Craig Muir, A Star for Seamen: The Stevenson Family of Engineers, London, 1978, p. 175:

"Of all the Stevensons, Alan was the most unusual engineer.  He had unquestioned abilities, and by [the 1840s] had already been presented with medals from the kings of Holland and Prussia and with a splendid diamond ring from Czar Nicholas of Russia for his lighthouse work."

In good overall condition consistent with age. The lid and the base of the box have come off. The lock is missing.
"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. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."