How To Value Opal - The 10 Factors
如何評估蛋白石 - 10 個因素
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How To Value Opal - The 10 FactorsOn a scale of one to ten Opal is easily the hardest gemstone to try and value. Opal has an infinite number of variables including color, pattern, brightness and origin. Opal has a complicated classification system for valuations that is much harder than diamonds or any other gemstones.

If you are ready to take the plunge and purchase your first Opal or if you are an avid collector, this article is going to walk you through the 10 factors that contribute to the final price of an Opal.

Given that there are 10 separate factors that con contribute tot he final price of an Opal, there is a certain degree of movement in pricing. Many Opal miners can under or over value their opals when it relates to supply and demand and what market they are selling to. Many buyers on Opal Auctions use our ITEM WATCH to track what Opals sell for.

Over many years there has been guidelines developed on how to value Opal. We are going to explore the 10 factors that contribute to an Opals final value. These factors are:

  1. Color
  2. Direction / Play Of Color
  3. Pattern
  4. Body tone
  5. Brightness
  6. Shape
  7. Inclusions
  8. Which Opal Field
  9. Natural vs Treated
  10. Country Origin

How Opal Is Valued In Lightning Ridge, Australia

At Lightning Ridge in Australia, they have a committee that values opal miner’s opals each Saturday. Several experienced opal valuers will price the opal per carat and the final value will be determined by the average price per carat. The above factors can vary from person to person and that is the reason you may see variation in price per carat amongst miners.

During this article if you are not sure of any of the terms, checkout our glossary for an explanation on just about everything spoken in the Opal world.


Color is the first thing that you will notice about an opal. Red is the rarest and most sought out color. In order of value, the most valuable color is red, then orange, green, blue and purple. However, Opal is usually never a single color. It is important to decide what the dominant color is followed by any secondary colors. Use the dominant color as the color that will affect the price.

Some Opals of note would be the red Opal with a purple hue color bar hidden inside. This will create a deep majestic red color. Also electric blue Opals are more valuable as the hidden color bar makes the Opal brighter than the normal blue.

Density and intensity of color is also important to determine the price. The thickness of the color bar can help to amplify the brilliance of the Opal color. Seam Opal generally has a thinner color bar than opals formed in a knobby.

How To Value Opal - The 10 Factors Guide  Opal Auctions


Opals are a gemstone that dramatically change appearance based on what angle the Opal is viewed at. When an Opal is at it’s brightest, this is called ‘facing’. The direction of color can affect the price becuase it will determine how versatile the Opal is. If it only faces in one direction, it may only be suitable for a Pendant for example.

  • Opals that face with strong fire from all directions make good ring stones. These Opals are very versatile and are more valuable than one directional opal. A fine quality Opal will look good no matter what direction it is viewed at.
  • An opal that faces in one direction is ideal to make into a pendant. The jeweler will set it in the right direction so as to show as much of the fire as possible.
  • Some multi-color opals might have 1 or 2 strong colors that have different directional faces and these can be hard for jeweller to set. 
  • Dead spots are when no color is visible from a certain angle. These will lower the overall value of the Opal.


Opals that have a rare or unique pattern are more valuable. The Harlequin pattern is the rarest and most loved pattern in opals but it is very rare. A True harlequin pattern is a mosaic broad pattern, angular close set of colors. Floral patterns are sometimes called floral harlequin.

Some top patterns are Mackerel, Block, Broad flash, Rolling flash, Pinfire, Rainbow and most sought out Ethiopian opal is the Honeycomb pattern. Opals that have no or only slight pattern are generally less valuable.

How To Value Opal - Pattern - Mackerel Pattern Opal


The Opal Body Tone Guide was endorsed by the Opal Association of Australia and was intended to be a guide for Black Opal and Boulder Opals. It is now generally excepted for all opals worldwide. Opals are grouped in 9 sub categories N1 to N9 with N1 the darkest opal and N9 the lightest.

  • Black opals are generally the most valuable and have a body tone of N1 to N4 
  • Opals with N5 to N6 considered a semi black or dark opal. 
  • Body tone N7 to N9 are called crystal opals.

How to value opal - the base body tone chart


The Opal brightness guide was produced by the Australian opal association along with the body tone guide. There are 7 sub Brightness ratings with B1 the brightest to B7 the dullest. The brighter the Opal, the more expensive will be its value. How to value opal - the brightness chart


Oval stone are generally considered more valuable than free form, except with boulder opals where free form is considered desirable. The shape of the Opal once again determines how versatile it is. Oval stones generally have the best face of color and can be used in a variety of applications.

Opal is almost always cut in a cabochon. A cabochon stone is more valuable when it has a high dome compared to a a flat stone. This is due to the fact that cabochons make ideal ring stones but flat stones are less desirable because they cannot be used in many jewelry designs.


Inclusions and potch lines and are not to be confused with cracks. A crack line reflects light and greatly devalues an Opal. It is worth reading about the difference between crazing and cracking in an Opal.

A potch line has no light reflection and these opals are generally valued lower but can make artistic picture patterns. 

Some Opals will have a vegetation pattern from the inclusions and this is popular as the opal has replaced some of the tree or vegetation. Sand or windows also reduce the value of the opal. A window is a gap on the bottom where potch has not formed and opal is transparent.

Ethiopian opal can have a ghost or phantom inclusions or vegetation matter. These types of inclusions are generally accepted as reasonable in this type opal. How To Value Opal - Inclusions


The end buyer or wholesaler might not be able to consider this factor. But in the trade certain mines have a reputation of producing good quality rough that makes excellent stones. This happens in Australian and Ethiopian opal fields. Even the depth of the mine can greatly effect value.

In the trade, this can be an important factor for repeat buyers. If you find a seller has certain stocks that you like, it is best to purchase from that group. 


Natural Opal is always valued higher compared to treated Opal. Over the last few years smoked or treated Ethiopian crystal opal has been sold as natural Black Opal. This treatment is not permanent. Opal Auctions has sellers who must clearly state that the opal is treated. Unfortunately we now see lots of fake opals offered for sale, not only online but also spiced in parcels of rough opals. 

Fake Opal or synthetic Opal is also somethng to watch out for. It is best to educate yourself on how to spot a fake Opal.

Opal doublets and triplets do not have the same stringent criteria as solid opals and are valued considerable less. It is important to be able to pick a doublet opal compared to a solid and this can be difficult when the opal is set into jewelry. Checkout these resources:


Australia has a worldwide reputation as the world’s most expensive opals. Many countries now produce good opals like Ethiopia, Mexico and Brazil. Each country’s opals may be unique and this factor helps determine the Opal price.


如何評估蛋白石 - 10 個因素在 1 到 10 的範圍內,蛋白石很容易成為最難嘗試和評估的寶石。蛋白石有無數的變量,包括顏色、圖案、亮度和產地。蛋白石有一個複雜的估價分類系統,比鑽石或任何其他寶石難得多。

如果您準備冒險購買您的第一塊蛋白石,或者如果您是一位狂熱的收藏家,本文將帶您了解影響蛋白石最終價格的 10 個因素。

鑑於有 10 個單獨的因素影響蛋白石的最終價格,定價存在一定程度的變動。許多蛋白石礦工在與供求關係以及他們的銷售市場相關時可能會低估或高估他們的蛋白石。 Opal Auctions 上的許多買家使用我們的ITEM WATCH來跟踪 Opal 的售價。

多年來,已經制定了關於如何評估蛋白石的指導方針。我們將探討影響蛋白石最終價值的 10 個因素。這些因素是:

  1. 顏色
  2. 方向/色彩遊戲
  3. 圖案
  4. 身體色調
  5. 亮度
  6. 形狀
  7. 夾雜物
  8. 哪個蛋白石場
  9. 天然與處理
  10. 國家起源


在澳大利亞的 Lightning Ridge,他們有一個委員會,每週六對蛋白石礦工的蛋白石進行評估。幾位經驗豐富的蛋白石估價師會對每克拉的蛋白石進行定價,最終價值將由每克拉的平均價格確定。上述因素因人而異,這就是您可能會看到礦工之間每克拉價格存在差異的原因。






如何評估蛋白石 - 蛋白石拍賣的 10 個因素指南



  • 面對來自四面八方的強烈火光的蛋白石是很好的戒指石。這些蛋白石用途廣泛,比一種定向蛋白石更有價值。無論從哪個方向觀看,優質蛋白石都會看起來不錯。
  • 面向一個方向的蛋白石是製作吊墜的理想選擇。珠寶商會將其設置在正確的方向,以便盡可能多地展示火光。
  • 一些多色蛋白石可能有 1 或 2 種具有不同方向面的強烈顏色,珠寶商很難鑲嵌這些顏色。
  • 死點是指從某個角度看不到顏色。這些將降低蛋白石的整體價值。


具有稀有或獨特圖案的蛋白石更有價值。 丑角圖案是蛋白石中最稀有和最受歡迎的圖案,但非常罕見。真正的丑角圖案是馬賽克寬幅圖案,角度接近的一組顏色。花卉圖案有時被稱為花卉丑角。


如何評估蛋白石 - 圖案 - 鯖魚圖案蛋白石


Opal Body Tone Guide得到了澳大利亞蛋白石協會的認可,旨在成為黑蛋白石和博爾德蛋白石的指南。現在,全世界的所有蛋白石都被排除在外。蛋白石分為 9 個子類別 N1 到 N9,其中 N1 是最暗的蛋白石,N9 是最輕的。

  • 黑蛋白石通常是最有價值的,體色在 N1 到 N4 之間
  • N5 至 N6 的蛋白石被認為是半黑色或深色蛋白石。
  • 體色 N7 至 N9 被稱為水晶蛋白石。

如何評估蛋白石 - 基體色調圖


蛋白石亮度指南與身體色調指南一起由澳大利亞蛋白石協會製作。有 7 個子亮度等級,B1 最亮,B7 最暗。蛋白石越亮,其價值就越高。 如何評估蛋白石 - 亮度圖表





夾雜物和斑點線不要與裂紋混淆。裂紋線反射光線並大大降低蛋白石的價值。 關於蛋白石開裂和開裂之間的區別,值得一讀。

potch line 沒有光反射,這些蛋白石通常價值較低,但可以製作藝術圖案。


埃塞俄比亞蛋白石可能有幽靈或幻影內含物或植被物質。在這種類型的蛋白石中,這些類型的內含物通常被認為是合理的。 如何評估蛋白石 - 內含物





與處理過的蛋白石相比,天然蛋白石的價值總是更高。在過去幾年中,熏製或處理過的埃塞俄比亞水晶蛋白石已作為天然黑蛋白石出售。這種治療不是永久性的。 Opal Auctions 的賣家必須明確說明蛋白石經過處理。不幸的是,我們現在看到大量出售的假蛋白石,不僅在網上出售,而且在原石蛋白石包裹中添加香料。






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Excellent , information ,very helpful and much appreciated ,thank you.

7th Jul 2021

Very helpful indeed.

21st Jun 2020

I found it to be very interesting always go back to the basics basics her where it's at a beautiful baseball player that can't hit any more they take him back to the basics always love review in that

27th May 2020

Advice very helpful

16th Jun 2018


7th May 2018

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