How to buy an opal - white opal diamond ring rose gold ring

Natural Opal buying guide – How to check and understand difference between different opals?

Opal is one of the most popular phenomena gemstones. They display very unique characteristics like ‘play-of-color’ or different background fire colors.

They are quite abundant but also rare as well depending on the quality grades. Different quality has different price levels which we will explain below.

How to Buy an Opal – Opal Classification

In trade, we classify opals in the following categories.

  • Black Opal background color can range from translucent to opaque to dark grey. But it should appear black in reflected light. They also show a play of color.
  • White Opal background color can range from translucent white to medium gray. They also show a play of color.
  • Crystal Opals background color can range from transparent to semitransparent. They show an exceptional play of color.

*Example of Crystal Opal we just custom made for our client – details can be seen here on our Facebook page.

  • Water Opal background color range from transparent to translucent. It shows a faint play of color or no play of color at all.
  • Boulder Opal include fragments of the host rock or matrix as part of the finished gems. It shows a play of color.
  • Fire Opal background color range from transparent to translucent red, orange or yellow. It might or might not show a play of color.
  • Assembled Opal is made of layers of opals or a layer of opal and other material put together. This will improve the appearance and durability of the stone.

How to Buy an Opal – Price Value of Opals

To determine the value of an opal, in simple terms, we look at three aspects

  • Color – Background color and play-of-color
  • Pattern – Arrangement of play-of-color
  • Clarity – Transparency and amount of inclusions

How to Buy an Opal – Background Color 

In terms of price, black opal commands the highest prices of all opal types and a single black opal of exceptional quality can sell for tens of thousands of dollars.

Due to its unique qualities, black opal usually sells by the piece rather than by carat.

How to buy an opal - Black Opal Image
Black opal commanding a price of £72,000 ©

White opals make the majority of commercial-quality opals in the market and that is why they are most familiar to consumer market.

White opals come in large ranges as described below:

  • Commercial qualities – Usually pale and cloudy yellows or browns with very faint scattered play-of-color
  • Top-qualities – almost transparent gems featuring distinct patterns of crisp, lively play-of-color.

Due to these large ranges, white opals can range less than one dollar per carat to more than a few hundred dollars per carat.

How to Buy an Opal – Play-of-Color

Desirable play-of-color is further broken down in hue. In the trade, red is considered most desirable, then orange followed by green.

However, favored hues can vary with fashion or personal preference.

How to buy an opal - 5 carat white opal with strong flash 'play-of-color'
5 carat white opal we sold a client which displays strong flash ‘play-of-color’

It is quite difficult to determine what the dominant play-of-color is in an opal as different viewing angles can change what dominant hues is. For example red might dominate in the same portion of an opal cabochon where blue dominates when viewed from a different angle.

Fire opals are unique in terms of having different background colors, from red through orange to yellow is valuable. Therefore value can be determined by both background hue color and play-of-color, unlike the other opal types which is usually exclusive to play-of-color.

The top color is usually red-orange to bright red and color is uniform throughout the gem. Opal experts usually avoid fire opals with a cloudy look as this is the sign that the stone is drying out and in danger of cracking.

Fire opals also sometimes come in faceted stones when they have no play-of-color, while the ones which do come with play-of-color are cut as cabochon.


Pattern is the arrangement of an opal’s play-of-color. The industry uses three general categories:

  • Pinfire – Very small patches or “dots” of play-of-color
  • Flash – Large areas of play-of-color
  • Harlequin – Large, distinct, usually rectangular patches of play-of-color with edges touching each other.

In general, people in the trade prefer large, closely arranged patches of color, over tiny, scattered dots. Again the most valuable opals have ‘bright’ play of color.

For an opal to have high rating or value it must have highly vivid ‘play-of-color.’ Also, opals which have ‘entire spectrum’ of color are considered very rare and valuable. Most opals are multi-color but won’t display all the colors and will have one main color and two or more secondary colors.


With an opal clarity is its degree of transparency and freedom from inclusions. Clarity value is again determined by what the opal’s background color is.

For example, crystal opal experts admire the transparency, while in black opal they prefer an opaque background. In the end, one has to see what clarity works best for each type of opal that helps display ‘the most play-of-color.’

Contact us today to get all your wholesale gemstones, diamonds and jewelry needs.  We can Source, Search and Supply anything you require.

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3 thoughts on “Natural Opal buying guide – How to check and understand difference between different opals?”

  1. Jaidev Merchant

    Very informative article. Thanks for sharing and letting me know what to look for.

    1. Thank you Phuphaji for your kind words. Will be posting some more articles in the next few weeks. Regards, Tarun Gupta

  2. heneelshah

    Opal Diamond Jewellery looks gorgeous and gives a classy look to you. Opal Diamond Ring is special for occasions.

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