Types Of Opals

Types Of Opals - black opalThere are so many types of Opals on the market that it can sometimes be overwhelming to try and identify them all. Lucky for you at Opal Auctions we have all the different types of opals so you can easily explore and understand the difference between them. In this article we are going to explain each of the different types of opals including Black Opal, Crystal Opal, Boulder Opal, Yowah and Koroit Opal and the smaller Opal fields like Mintabie and Tintenbar. Also we will talk about the important international Opals from Ethiopia, Mexico, Honduras, African and South American Opals.


Andamooka Opal

It is only a very small Opal field but is known for its treated matrix Opal sandstone and has spectacular colours.

Australian Fire Opal

This Opal field is only new and situated in the deserts of Western Australia and the Ppal has resemblance to Mexican fire Opal. It comes in brilliant sun burnt orange to red colours.

Black Opal

Black Opal is by far the most popular and well know type of Opal. It is characterized as Opal that has a dark body color. To understand how to judge the body tone of an Opal be sure to check this article.

Take note that the term Black Opal does not mean that the Opal is dark or dull. Some of the brightest and most beautiful opals are Black Opals. The term simply refers to the body tone of the stone.

types of opals - Black opal from lightning ridgetypes of opals - Black opal from lightning ridgetypes of opals - Black opal from lightning ridge

Most black Opal is mined in Lightning Ridge, NSW, Australia. When people talk about Black Opals they are referring to stones that have come from this region.

Dark Opal

Dark Opalis Opal that has a dark base but that is not dark enough to be called Black Opal.

Using the Base Body Tone chart you can see that a Black Opal has a body tone of N1 to N4. Dark Opal however has a body tone of N5 to N7.

body base tone guide for black opal

Types of opals - dark opalTypes of opals - dark opalTypes of opals - dark opal

White Fire Opal

White Opal refers to Opal with a white milky body tone. Most of this type of Opal comes from Coober Pedy in South Australia. While this Opal is beautiful it does not show off the Opal colors as well as the Black Opal.

This is because Black Opal amplifies the colors with the contrasting dark background. Most White Opal have muted pastel colors.

Types of opals - white opal from coober pedyTypes of opals - white opal from coober pedyTypes of opals - white opal from coober pedy

Boulder Opal

Boulder Opal is Opal that has formed along with another rock called ironstone. Most of this type of Opal comes from the Opal fields in Queensland where there is a huge belt that spreads thousands of kilometers where this type of Opal is produced.

The main thing to notice with Boulder Opal is the striking red ironstone that is present within the Opal.

Types of opals - boulder opalTypes of opals - boulder opalTypes of opals - boulder opal

Within the realm of Boulder Opal there are various types which deserve their own mention-

  • Koroit Opal - This Opal is so unique because it has such an amazing appearance. The cracks in the ironstone are filled with precious Opal giving it such a beautiful look. This Opal is very similar to Matrix Opal however, Koroit Opal has pure ironstone as the main stone
  • Yowah Nuts - These are only found in Yowah, Queensland. They are nodules of Opal that when cracked open can contain a pocket of solid precious Opal. Most of the nuts that are mined do not contain anything but every now and then a spectacular Yowah Nut is unearthed.
  • Matrix - This type of Opal can be a matrix of ironstone and other stones together with precious Opal. It can also be a matrix of sandstone, clay and ironstone.
  • solid matrix opals from Andamooka are much more expensive than concrete matrix in rough.

    The term “sugar treatment” refers to carbonization. Also, because there are other methods to change base color of matrix opals than just boiling in sugar and acid and the result is the same: filling pores with carbon.

  • Fairy Opal - Boulder Opal is natural but Boulder Fairy Opal is cooked sandstone Opal and therefore treated.
  • Mintabie Opal - Famous for creating milky white and sometimes Black Opal. It is located in South Australia and has produced some of the largest, most beautiful Opals in the past.
  • Tintenbar Opal- A very small volcanic Opal field in NSW, the Opals are not very stable and are deep dark hues and make excellent doublets.

Opal Fossils

Australia once had an inland sea millions years ago, so today you can find, if your lucky opalised marine life including sea shells, belemites and opalized marine life to remains of huge dinosaurs. It is rare to find pieces that are opalised but many collectors enjoy these unique specimens.

Pink Opal

Also a new Opal field in Western Australia which is a variety of Mookaite and has a really good polish and predominantly opaline silica with a high vitreous luster.

Crystal Opal

Most Crystal Opal is Opal that is clear like water. It has flashes of color on a clear jelly body. It is important to note that crystal Opal must be transparent to semi-transparent. In rarer cases crystal opal can actually be dark (semi-transparent) which gives rise to terms like Black Crystal Opal.

Opal Doublet

Opal doublets represent a great opportunity to own an Opal with amazing color at a fraction of the price of a solid Opal. They are created when a layer of precious Opal is glued to a backing that is strong. Usually it is ironstone, black potch or plastic.

Opal doublets are made from natural Opal that has been mined out of the ground. In many cases the Opal is too thin to use by itself so it is glued to a backing to add strength.

Opal Triplet

Just like an Opal doublet, anOpal triple has a backing usually black plastic or potch, a thin layer of Opal that is then covered by a piece of clear Quartz. The Opal used in a triplet is thinner than that used in a doublet and so the top of the Opal also also needs to be protected by a piece of clear Quartz.

Mosaic Opal

Mosaic Opal is created in the same way as an Opal triplet however instead of a single piece of opal being used a bunch of matching opal chips is used instead. It gives the piece a very unique and beautiful appearance.


Ethiopian Opal

This is the newest Opal that has become extremely popular in recent years. it is a volcanic form of Opal that has neon 3D colors. The low prices of Ethiopian Opal added with the beauty of Ethiopian Opal makes it one of the most desirable Opals available on the market today.

Tanzanian Opals

This country has honey coloured to green colored Opal known as Prase Opals and also some Dendretic Opals.

Madagascar Opal

Recent discoveries include Pyrophane or Gilarsol Opal with unique inclusions.

Kenyan Opal

Opal was first discovered in Kenya around 4000 BC. Today Opals are sold as Kenyan Opal which most likely come from the Ethiopian Opal fields.


Mexican Opal

Mexican Fire Opals and Contra Luz Opals can be clean stones or combined with soft brown potch and are volcanic Opals.

Brazilian Opals

Most are white semi translucent crystal Opals and considered stable and have unique patterns.

Peruvian Opals

Peruvian Opals from the Andes Mountains have been popular for their clean pink or Sea Blue colour and are called Andrea Opal or Paraiba Blue Opal.

Honduran Opals

These volcanic Opals are mostly milky white to matrix in colour. They are sometimes referred to as Honduran Black Opal matrix.


American Opals are spread all over the country in pockets from the Virgin Valley in Nevada to Utah. Oregon and Spencer Opal are not consider super stable and must be kept in jars of water to stop them from cracking.


This green coloured Opal is known as Opalite. The country did have volcanic dark colored Opals but today most are from the Ethiopian Opal fields and known as Kalimay Black Opals which is smoked Ethiopian Opal.


In ancient times Hungary supplied Europe with Opals. Slovakia was apart of the Hungarian Empire and the opal were referred to as Hungarian Opals. Today it is known as Slovakian Opals though. 


Dentretic Opal

Dendretic Opal can be found in several countries and is known as Moss Opal or Tree Agate.

Opalized Wood Opal

This refers to Opal that was once timber or vegetation and was opalized over millions of years .It can be referred to as USA Opal or Boulder Opal.

Hyalite Opal

This colourless Opal is found in Mexico and Australia and has a glass like appearance.

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