New York City based auction house Guernsey’s has announced the auction of the Marcial de Gomar Collection of rare emeralds on April 25th, 2017.

Included in the auction will be the “la Gloria”, an 887ct piece of rough emerald, said to be of “museum quality”. Believed to be the largest rough emerald in the United States, the golf-ball size stone hails from the Muzo Mine in Colombia.

The Marcial de Gomar Emerald Collection consists of more than twenty loose emeralds (both cut and rough) plus thirteen pieces of emerald jewelry and were collected by Manuel Marcial de Gomar over a long career spent both in the United States and in the jungles of Colombia. For years, Marcial de Gomar, worked in the legendary Muzo mines, widely known for producing the world’s finest emeralds.

The Collection also includes the largest assemblage of cut emeralds from the famed Nuestra Señora de Atocha sunken galleon and, among these, the single largest cut emerald recovered from that ship, considered the most important wreck site yet discovered

Arlan Ettinger, founder and president of Guernsey’s notes, “It’s very rare for an auction to spotlight emeralds. We feel this will be an extraordinary event.”

Although de Gomar estimates that a 400ct stone could be cut from the rough, he feels that la Gloria shouldn’t be cut but should instead be housed in a state museum.