EOSC 118 Lecture Notes - Lecture 13: Benitoite, Axinite, Peridot

• School: UBC
• Department: Earth and Ocean Sciences
• Course: EOSC 118
• Professor: David Turner

Document Summary

Describe briefly the significance of emerald and aquamarine through history. Emerald: the vibrant green variety of beryl one of the most valuable gemstones available its intense colour has been appreciated as far back as ~ 1500 b. c. in egypt has been coveted in ancient greece. Well-known in ancient india and recently in south america ancient aztecs used emeralds in jewelry and ceremonial items. Most magnificent (new world) emerald recently in colombia, south america. Because their crystals consist of closed, ringlike circles of tetrahedra that share corners. Each tetrahedron shares 2 oxygen atoms with other tetrahedral, and the rings formed may have 3 members (benitoite), 4 members (axinite) or 6 members (beryl) Common beryl ranges from tan to pale green, pale or sky blue, or yellowish. It is a minor constituent of many granitic rocks. Beryl is derived from greek beryllos, applied to many green stones. Beryl production is a byproduct of feldspar and mica.