Friday, September 23, 2011

Identifying Gems: Describing Color

I may, or may not, have mentioned at some point that I am a Gemologist. What on earth does that mean? Along with a lot of other things, I learned how to put a gem through a series of tests to determine its identity. Because I earned my degree at the Gemological Institute of America, I will be using their terms and descriptions. Other gem labs may use different terms.

The gem identification process separates gemstones by a combination of eliminating options through positive test results. A gemstone needs, at minimum, three positive results. Some require additional testing.

To begin, I describe the color: hue, tone, and saturation. Pigeon's blood red, cornflower blue, and grass green may evoke pretty pictures, but they fail to describe the characteristics if a color in a scientific manner. For that, I turn to a special color wheel and two scales.

The color wheel provides a range of hues to compare my gem to:

Tone describes how light or dark a gem is.

Saturation describes how strong or weak the hue is.

The color description of this stone color can be parsed two ways: Medium dark, moderately strong, slightly yellowish green (tone, saturation, hue). Or, slyG 6/4 (hue tone/saturation).

Next time: transparency.


Carole said...

I really like that. If everyone used the same method, it would make it so much easier to buy things on the internet. Very interesting post; I'm looking forward to the follow up.

mcstoneworks said...

Great information, Andrea.

Thank you for sharing your expertise.

MmeMagpie said...

It would, wouldn't it?

The nice thing about the scientific notation is that two people who are familiar with the system can talk to one another and know exactly what colors are being discussed. One person's cornflower blue may be different from another's. Medium, vivid, violetish blue is exactly that.

Over the coming weeks I'll walk through the entire gem identification process and describe each test to the best of my ability.

Cat said...

Very interesting!

Bonnie said...

Great post Andrea. Color is one of the most difficult things to describe. There are so many interpretations. I appreciate a scientific basis for color names.

Rita alias alatvian said...

Thank you so very much
Great info!

galadryl said...

Great info, thank you very much.

AMDesignsbyAngela said...

Great information, Andrea...thanks for sharing. I look forward to more in this series.