Byzantine Empire, probably Imperial workshops in Constantinople, circa 1000 – 1100 AD
This museum quality Byzantine bloodstone cameo is finely carved in high relief with image of Christ Pantocrator (The Ruler of All). Abbreviation ‘IC XC’ stands for Jesus Christ.
The lightest part of the stone is around the nimbus that was done to enhance the image of Christ. The relief of the head projects farther from the background than the body to highlight the appearance of Christ. The diamond shaped lock of hair on His forehead is specific to iconography of Christ of the 10th and 11th centuries.
The cameo is set in a 19th century custom-made silver bezel embellished with cabochon cut amethysts and mounted as a pendant. According to the engraved French inscription on the back of the bezel, the cameo was purchased in Paris and gifted by prince Urusov to count Musin-Pushkin on the 16th of April 1859.
Counts Musin-Pushkin and Princes Urusov are old Russian aristocratic families. Apparently, the recipient of this cameo whose name is engraved on the bezel is Count Alexei Ivanovich Musin-Pushkin (born in St. Petersburg in 1825 and died in Nice, France in 1879). He was the chairman of the consul of Saint Petersburg nobility (1858-1859), marshal of the Imperial Court (1866) and minister of the Court (1869). His family is known to collect ancient Russian and Byzantine artifacts for few generations.
The cameo measures 28 x 27 mm (1 1/16 x 1 1/16 in.)
Diameter of the silver bezel is 41 mm (1 5/8 in.)
The quality of the carving of this cameo appears to be superior to the other four bloodstone Byzantine cameos of Christ in the major museum collections:
the Cabinet des Medailles in Paris
the British museum
https://www.britishmuseum.org/collection/object/H_1859-0301-94?selectedImageId=1602142001
the Kunst Historisches museum in Vienna
https://www.khm.at/en/artworks/christ-pantocrator-74752-1
ex-Catherine the Great cameo from collection of Duke of Orleans in Paris purchased by the empress in 1787 and now at the Hermitage museum.
There is a fine bloodstone cameo of Christ in the Penn Museum. You may learn more about the iconography of Christ in Byzantine art here: