Gemval logo
Reference Values of Gems
Database updated: 1 Oct 2015
  Sign up Log in

Online gemstone appraisal

Gemval provides you web tools for gemstone appraisal, whereby most natural gemstones can be valued using our interactive model. To arrive at the value our statistical model takes into account the many factors contributing to gem's value. Factors such as the stone's variety, carat weight, color, saturation, clarity and others are all used in the calculation. The value displayed by the model represents average market prices for the stone as of the date of appraisal.

Gemstone price calculator

Current market prices of gemstones

Carat value charts published by Gemval represent average retail prices of natural gemstones. We update our value charts on a monthly basis.

Gemstone value charts

Gemstone color grading

The color grade matrix is the core of the Gemval online appraisal system. It consists of 230 color patterns, 25 base hue sets and a grey scale. This is extended by 6 tone levels (very light, light, medium light, medium, medium dark and dark) and by 3 saturation grades (strong, very slightly greyish-brown and slightly greyish-brown).

Color grade system

Color grades for Opals

Service news and upgrades log

September 29, 2015
Benitoite section updated.

September 28, 2015
Amethyst, Ametrine, Citrine, Quartz sections reworked.

July 1, 2015
Aquamarine, Beryl, Zultanite sections reworked.

Previous events

Gemstone market average index (GVA) for the past 12 months.

Historical Prices and the Gemval Aggregate Index

We have monitored and recorded historical prices for natural gemstones since the 1st of July 2005. The Gemval Aggregate index (GVA) is updated monthly on the basis of calculated values and past statistics. GVA reflects the overall pricing trends for natural colored gemstones.

Historical data charts

Gemval Aggregate Index


We grant our visitors free access to most gemstone pricing data. However access to data is reserved for subscribers on the following stones:
- Alexandrite
- Diamond, Fancy Diamond
- Emerald
- Opal (Australia, Ethiopia)
- Ruby (heated / unheated)
- Sapphire (heated / unheated)
- Spinel &
- Tanzanite

Subscription fee:
$24.00 - 1 month
$38.00 - 3 months
$54.00 - 6 months
$82.00 - 1 year.

As a subscriber, you'll have access to all of Gemval's functions and, of course, you will benefit from our highest priority customer service.

To subscribe please register and login


Gemval logo Color grading system
Color system for opals
Clarity grades
Gems info
How it works
Privacy Policy
Site Map
About us