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.

Physical properties:

Optical properties:

Cutting Angles (culet/crown):

Cutting Lap:

Any grade

Facet Polishing:

Cabochon Polishing:

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).

Beryl rough

Beryl on Gemdat