Descriptions

Buying rough is an art form in itself. Learning to judge the quality of a crystal requires seeing inside the rough to the often hidden inclusions, judging the shape of the rough to discern the type of gem that might be carved, and understanding the cost/recovery equation.

In coming months, these topics and more will be discussed in the Gemscapes blog:

Portfolio of rough

Rough, rough, rough, can you ever have enough?

Obtaining rough gems

With our upcoming trip to Tanzania there will be much to tell!

Recovery in rough

Many people are shocked to hear that carving or faceting a gemstone requires a huge loss of rough.

Thirty percent recovery is considered to be good. This means that seventy percent of the gem will be ground away in the cutting process.

Fifteen percent recovery is considered to be low. This means that eighty-five percent of the gem was ground away in the cutting process.

Whether you get high recovery or low recovery when cutting gem rough is an important issue for any working lapidary. Gem rough is expensive, and a bad judgment about expected recovery from an expensive crystal can be financially treacherous.

Treatments

Gems can be heated, irradiated, dyed, or altered in many different ways. If you are looking at one of Sherris' gems, we will always tell you if it has been treated. Most of the gems that Sherris carves are not treated at all, but there are a few, such as aquamarine and tanzanite that are routinely heated to enhance the color.

Heating a gemstone generally involves burying it in sand or some other compound, putting it in a kiln and slowly raising the temperature until the desired color is reached. The gem is then allowed to cool slowly. There is no way to tell if a gem has been heated, and in most cases heating does not damage the gem structurally. Often heating is done at the mine, but lapidaries also heat single gems individually. Gems that are sometimes heated include, aquamarine, citrine, amethyst, tanzanite, tourmaline and blue zircon.