Opals are precious and unique gemstones. They are in a class of their own because they are not crystals and do not follow the usual guidelines of the 4 C’s. They are valued for their “play of color”- the optical property that causes bright colors to flash across it. Precious opal is usually cut en cabochon to best display this play of color. Opals are soft and brittle relative to other gem materials, and are therefore better worn in necklaces and earrings rather than rings and bracelets, or at least given protective settings.

Learn More About Opals

How the TYPE affects the value of an Opal
How COLOR affects the value of an Opal
How PATTERN affects the value of an Opal
How CUT affects the value of an Opal
Opal treatments and synthetics
Opal meaning and symbology
Opal myths and misconceptions

The Most Valuable Opal

The most valuable opal are black precious opal with regular “harlequin” patches of color which include plenty of red and violet. They are large (over 7 carats) cut in a cabochon with a high dome.

Least valuable: This opal is very small. It is otherwise typical white or “crystal” opal with no spectacular play of color. Opals like these are quite common. One of them would cost less than $100. Moderate value: This opal is of about the same quality as the previous opal but it is more valuable because of its larger size. High Value: This is a white or “crystal” opal with excellent play of color with plenty of reds and purples and large size. An opal like this is hard to find and can cost a few thousand dollars. Most Valuable: This is an exquisite opal. It is more valuable because it is a black opal and has excellent play of color with large areas of red. The stone itself is also quite large (over 10 carats). An opal like this will certainly cost thousands of dollars.

Here are some large photographs of different opals and an analysis of their value.

Here is a white opal of average quality and large size. The play of color is weak: we can see much more white than we can see of colors. The color that does appear is in “pin point” patches, which is relatively common and less valuable.
This is a large opal with a very nice play of color. The color is in a “harlequin” pattern which is very valuable. This particular peice looks like it needs to be re-polished: the surface does not shine like it should.
This is a jelly opal. It is not acceptionally rare. The play of color is less fiery and more watery. Opals like these are less common in jewelry, although recently it has become popular to facet them.
This is the kind of opal you typically find in any jewelry shop. It is not rare, especially valuable, nor striking. The stones are small, very white with little play of color. They are commonly used as accent stones. Buy them if you just want to have an opal and you’re on a budget.
Here is an example of a very nice black opal. The strong red color makes it very valuable
This is a yellow Mexican opal with a very good color. These opals are in the same class with jelly opal: they are not especially rare, and display a watery play of color. This opal has been faceted: a recent trend. A faceted opal is especially vulnerable to being scratched since opals are soft.
An opal like this is something opal lovers wish to see in their lifetime. A very nice speciman of white crystal opal. It has a strong play of color, including valuable reds and purples and is a large size.
Here is a black opal with excellent play of color with strong reds and dynamic patterns. If you see this opal and you can afford it, buy it.
This is a Mexican fire opal. As with the yellow opal, it is not especially rare, and has a watery feel to it. People buy this kind of opal for its vibrant, glowing color.