Beryl


There are many color varieties of beryl. Emerald – green, Aquamarine – blue, Goshenite – colorless, Bixbite – red, Heliodor – yellow-yellow green, Golden beryl – lemon yellow-golden yellow, Morganite – pink-violet and salmon. There are also deeper green beryl not colored by chrome and therefore technically not an emerald.

Physics:

Chemistry:Al2Be3[Si6O18]
Hardness:7,5–8
SG:2,65–2,75
Cleavage:Non
Toughness:Somewhat brittle
Heat sensitivity:Non

Optical:

RI:1,57–1,60
Dispersion:0,014 (medium)
Birefringence:0,009 (weak)
Pleochroism:Varying
Critical angle:39,5°

Cutting Angles (culet/crown):

Vargas:43°/42°
Olson:43°/42°
Soukup:43°/42°
Roth:43°/42°
MDR:43°/42°
Schlagel:41°/37°
Perkins:43°/42°

Cutting Lap:

Any grade

Facet Polishing:

Vargas: Cerium oxide on acryl, Aluminum/tin oxide on tin or tin/lead
Olson: Aluminum/cerium oxide on acryl or tin
Soukup: Cerium/aluminum/tin oxide on tin or acryl
Christiansen: Aluminum oxide on tin or tin/lead, Cerium oxide on acryl, Tin oxide on tin
Herbst: Aluminum/cerium oxide or diamond on all common laps
Perkins: Aluminum oxide on BATT or Corian

Cabochon Polishing:

Olson: Tin oxide on leather, cerium oxide on felt
Christiansen: Aluminum oxide/diamond 50k/100k on leather/wood, cerium/chrome oxide on felt
Cox: Aluminum oxide on leather, Cerium/chrome oxide on felt
Covington: Cerium oxide on felt, Aluminum/chrome oxide on leather, Diamond on phenol

Orientation:

Best yield

Treatments/synthetics:

Beryl is heat treated or irradiated sometimes. Especially morganite is heated to remove the brown component and give it a more purple tone. Aquamarine is often heated to remove any yellow to make a greenish stone more blue. Emeralds are almost always treated with oil or epoxy.
Only emerald is synthesized. Synthetic aquamarine is in fact synthetic spinel or synthetic quartz. Quartz are being heated and rapidly cooled in green dye where it cracks and the dye fills the fractures. They are grinded and cobbed, and sometimes even given a fake matrix, and then sold to tourists as an "once in a lifetime" bargain. 

Tip!

Beryl is rarely troublesome for the cutter (more than the price). Golden beryl can lose its color if heated too much (>250 °C).

 
 

There are no products to list in this category.