Rare Antique Papal Solid Silver Locket Pendant With Pope Pius XI Coat of Arms

Rare antique, handmade of solid silver Papal locket - pendant of oval locket form with a chain from the pontificate of Pope Pius XI. 1922, to his death in 1939
On the face of the locket is a finely hand-engraved papal coat of arms of Pius XI. The interior is gold gilt. 
It is fitted with a suspension ring at the top and a trace link neck chain.
This type of gift was presented personally by the Holy Father at private audiences to prominent guests visiting the Vatican.
Pope Pius XI (Italian: Pio XI), born Ambrogio Damiano Achille Ratti (May 31, 1857 - February 10, 1939), was head of the Catholic Church from February 6, 1922, to his death in 1939.
He was the first sovereign of Vatican City from its creation as an independent state on February 11, 1929. He took as his papal motto, "Pax Christi in Regno Christi," translated as "The Peace of Christ in the Kingdom of Christ."
It is a rare, museum-quality papal relic associated with Pope Pius XI. We have been over 45 years in the antique business, and for the first time, we were fortunate enough to acquire such a rare object. 
We searched in all possible sources, including reference books, museum catalogs, and the internet, for other silver Papal lockets with the coat of arms of Pope Pius XI. 
We only managed to find two other silver locket pendants with the coat of arms of Pope Pius XI. Both are in a private collection. 
So there are probably only 3 of this type of locket pendant with Pope Pius XI Coat of Arms.
Dimensions:
Locket: 31 mm x 14 mm (1.2 inches x 0.6 inches)
Single chain length: 54 cm (21.3 inches)
Gross Weight: 14.6 grams (0.5 ounce)