Beryl
General Information
Beryl is one of the most important gem minerals. Beryl is colorless in pure form, though different impurities give beryl varied coloration. Without these color varieties, beryl would be an ordinary gemstone with only average fire and brilliance. Emerald is the green variety of beryl and Aquamarine is the blue variety.
The name beryl is used for the red and golden varieties, which are simply called red beryl and golden beryl, respectively.
Emerald is highly prized and is one of the most valued gemstones. Its green color is peerless; all other green gemstones are compared to its intensity. Emerald specimens are often "flawed" with mineral inclusions and fractures. Unlike other gems, these are considered part of the stones' "character." These flaws help determine natural from synthetically-produced stones. Uncut emerald specimens are rare on the mineral markets, probably because even low grade emeralds can carry a high price when cut as gems. Especially hard to find are true "in-matrix" specimens. Fakes are often produced with natural crystals glued into a "host" rock and then sold as an in-matrix specimen with a highly inflated price.
Aquamarine is also a popular gem although it does not command nearly as high a price as emerald. Uncut aquamarines are plentiful but relatively expensive, as would be expected of crystalline gemstone specimens. Large crystals of aquamarine are available on the open market and represent perhaps the largest raw gemstone specimens.
|
 |
|
|
Chemistry: Be3Al2(SiO3)6, Beryllium Aluminum Silicate
|
Class: Silicates
|
Subclass: Cyclosilicates
|
Color: Emerald Green, Blue, Yellow, Greenish-Gold, Red, Colorless, Pink
|
Streak: White |
Luster: Vitreous
| |
Transparency: Transparent to translucent
|
Crystal System: Hexagonal
|
Hardness: 7.5-8
|
Cleavage: Imperfect
|
Fracture: Conchoidial
|
Specific Gravity: 2.6-2.8
| |
Crystal Habits: Hexagonal prism with pincoid terminations. Often modified by different pyramidal faces which sometimes produce a rounded termination
|
Uses: Gemstone, mineral specimens, source of beryllium
|
Associated Minerals: Micas, quartz, euclase, calcite, tourmalines and some feldspars
|
Other Characteristics: Faces on crystals are often pitted; striated lengthwise and rough |
Notable Occurrences: Colombia; Africa; Brazil; Russia; Pakistan; California
|
Best Field Indicators: crystal habit, lack of good cleavage, hardness and color
|
|
|
