CLEAN : Spectacular emerald collection going to auction in New York

The video discusses an upcoming auction featuring rare emeralds, including those from the Musil mine and linked to the Spanish galleon Nuestra Senora de Atocha. The auction will showcase over 40 lots, with more than 30 rare emeralds ranging from uncut stones to those set in jewelry. A highlight is La Gloria, an 887-carat emerald, estimated to be worth $4 to $6 million.

What historical connection do the stones have according to the text?

What is the estimated value range for the stone referred to as La Gloria?