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
March 31, 2016
Opal (Australia) and Opal (Ethiopia) sections updated.
January 29, 2016
Orange Kyanite added to the database. Kunzite, Hiddenite sections reworked.
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:
- Diamond, Fancy Diamond
- Opal (Australia, Ethiopia)
- Ruby (heated / unheated)
- Sapphire (heated / unheated)
- Spinel &
$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