Gachala Emerald, is now at the Smithsonian. 



During the first half of the twentieth century, the 

 Colombian government was unable to mine profitably 

 at Muzo, and in 1946 the government yielded manage- 

 ment of the mine to the Banco de la Republica, the 

 national bank, which supervised it until 1969 with bet- 

 ter results. During this period, several emeralds of ma- 

 jor importance were found, and these were placed in 

 the bank's vault in Bogota, where they remain. They 

 include five crystals weighing 220.0; 1,020.5; 1,482.5; 

 1,759.0; and 1,795.85 ct each. Two of these— the 

 1,020.5 ct and 1,759.0 ct crystals — are of exceptional 

 quality. The latter stone, measuring 50 x 45 x 89mm, 

 may be the largest very fine rough emerald crystal in 

 the world. Certainly, these five together are comparable 

 to any emerald crystal collection known. 



For the most part, the five crystals are simple hex- 

 agonal prisms. The 1,795.85 ct and the 1,482.5 ct crys- 

 tals are definitely blue-green, a characteristic generally 

 associated with Chivor emeralds though all five in the 

 bank collection are reportedly from Muzo. They have 

 interesting rectangular etch faces, minor calcite inclu- 

 sions, and some associated pyrite. 



While under the bank's management, Muzo also 

 produced the largest Colombian emerald crystal in the 

 world — the 7,025 ct Emilia crystal from the Las Cruces 

 mine. It is of poorer quality, however, than those in the 

 bank's collection. The crystal has been displayed at var- 

 ious expositions around the world since its discovery in 

 1969 by a private mining concern, but its present 

 whereabouts is unknown. 



Today, the Muzo and Chivor districts remain Col- 

 ombia's chief emerald producers. The Muzo district, 

 360 square kilometers (139 sq. miles) in area, and at an 

 elevation of about 600 m, is 105 km north of Bogota in 

 the valley of the Rio Itoco, a tributary of the Rio 

 Minero. The main mines in the Muzo district include 

 the Tequendama, Santa Barbara, El Chulo, Coscuez, 

 and Penas Blancas. 



The Chivor district, some 75 km northeast of Bogota, 

 is in exceedingly rugged country where the Rio Rucio 

 and Rio Sinai join to form the Rio Guavio. The Chivor 

 mine is at an elevation of about 2,300 m, and just 2 km 

 to the east, in sight of the mine, the Rio Guavio, at an 

 elevation of only 700 m, slices through a ridge that rises 

 even higher than the mine. In addition to the Chivor 

 mine, the Chivor district includes the Buenavista mine, 

 just south of Chivor, and the Las Vegas de San Juan 

 mine, commonly known as the Gachala mine, some 8 

 km to the southwest. Colombia's only privately owned 

 emerald mine, Chivor has produced moderate but con- 

 sistent quantities of fine emeralds in recent years. In the 

 past year, the Buenavista mine has been particularly 

 active. 



Much of the recent excitement in the Colombia 

 emerald mining area has been at Muzo, a government - 



The most spectacular of five crystals housed in the Banco de la Repub- 

 lica in Bogota, Colombia, is this crystal which weighs 1795.85 ct. 

 Photo by Harold and Erica Van Pelt. 



Looking east over the Chivor emerald mine, 75 km northeast of 

 Bogota. 



