1987 Gemology : Control Stone

The Control Stone:

The material we used in the 1987 gemology has both green and blue colors, this type of turquoise was a common find in the 1980’s. This turquoise was a vein nugget in the mid-grade range of Stone Mountain Turquoise. It had some translucence on the green edges and was at least 6 mohs in hardness. We made a relief specimen shaped like Nevada out of the remaining material from the control stone, and it is the Nevada Cassidys logo. Here is a close up of the same type of material:

The Control Stone example

Allan E. Lombardo Gemology – Page 1Page 2Page 3

* Relief Specimen = A stone specimen that has been fully polished by a hand drill without a vice, such as a Foredom drill, while keeping the integrity of the natural shape of the stone. We use diamond bits for this process.


Add a Comment
  1. I have natural turquoise that I cut and polish using my dremel tool and diamond blades and bits. Is there anything I need to do with the finished product to stabilize it before I silver wrap it?
    Thank you– Mary Lou Venard

    1. if the turquoise is nice and hard you should not need to stabilize it. However one should always be careful when applying pressure to the stone when wire-wrapping. A lot of leverage can be applied with the wire and the tools used.

Leave a Reply

Your email address will not be published. Required fields are marked *

Time limit is exhausted. Please reload CAPTCHA.