Sierra de las Minas is a mountain range in eastern Guatemala which extends 130 km west of the Lake Izabal.

In 1990, a substantial part of the Sierra de las Minas (2,408.03 km2 or 929.75 sq mi, including the buffer zones and transition areas) was designated a biosphere reserve.

[1] Due to its size and great variety in elevation and precipitation, the range has many different habitats and land cover types, including:[2] The reserve has 885 species, about 70% of all species which are found in Guatemala and Belize, including threatened birds like the resplendent quetzal (Pharomachrus mocinno), harpy eagle (Harpia harpyja), and horned guan (Oreophasis derbianus).

Other mammals in the reserve include the red brocket deer (Mazama americana), the Guatemalan black howler monkey (Alouatta pigra), and the Baird's tapir (Tapirus bairdii).

[3] The southern area of Sierra de la Minas (translated in Spanish as the 'Mountain Range of the Mines’) is known for its rich deposits of jadeite, (one of the two forms of jade) marble, serpentine, and other minerals.

[4] Jadeite is found all over the world in countries including Myanmar, New Zealand, Kazakhstan, Russia, British Columbia, United States, and Turkestan.

The region of Sierra de Las minas as well as the Motagua river valley, was used by older Pre-Columbian era civilizations such as the Olmecs and Maya as a source of jadeite.

In 1999, Russell Seitz happened to be in one of these local jade shops in the town of Antigua when he noticed a large hand-sized sample of the rare blue-jadeite.

In 1996 prospector Carlos Gonzalez began searching the area for jade and he discovered a 140 lb boulder of jadeite which had a translucent, light blue color.

Gonzales and his colleagues discovered more jade examples in the southern tributaries of the Rio El Tambor located near Carrizal Grande and San José.

Other archeologists such as François Gendron of France and Dr. Richard Mandell of the University of South Carolina in Columbia began unearthing more samples of jadeite in the region.