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Opal Information

About | Types | Grading


About Australian Opal & Welo Opal

All opal, whether it be Welo opal from Ethiopia or Australian opal, are made from the same molecular structure - silica.  Silica is basically glass made from nature with a unique formation of molecules to create color. Australian opal is mined deeper than Welo opal.  The deeper in the ground an opal is mined, the more pressure it will have exerted on it and therefore the more water it will contain.  The main difference between Australian opal and Welo opal is the water content.  Some Australian opal wants to dry out (crazing) whereas Welo opal wants to absorb it (hydrophane).  Australian opal is around 6% to 8% water depending on the depth that it was mined and Welo opal is around 3% to 5% water as it is found in shallower ground.

Evidence of opal in Ethiopia was found in the late 1930's however it wasn't until the 1990's that mining began. This being said, antique or vintage Ethiopian opal jewelry is a misconception. (lie)
Welo opal has been mined since 2008 and the market for this is growing quickly.

Because Welo opal likes to absorb water, it should not be exposed to water for more than a minute or so if you want to keep constant color.  It will not hurt the opal but it will absorb water and diminish the color until it dries out.  This drying period can be from a few hours up to a few weeks depending on the amount of time it has to absorb water and what the drying conditions are like.

Any opal jewelry that uses resin to set the stone such as bell caps or inlaid opal, should never be exposed to water for any length of time.  Not because it will damage the opal, but because glues and resins do not take well to the quick change in temperature from water.  Quick temperature changes make the resins and glues expand and contract, therefore interfering with the bond between the two materials. i.e. Opal and gold or silver

 Ethiopian Opal vs Australian Opal?

 After reading the above information, should you choose Welo opal or Australian opal?
 It totally depends on you!
 Both are beautiful creations of nature and come in various sizes and colors.
 Welo opal is fairly new to the market and becoming very popular even with it's unusual characteristic.

Interesting tidbits about Australian Opal

Opal was #2 with Emerald being #1 in ancient times
Opal was also considered a lucky gem.  Now you are lucky to own a piece of Australian opal as quantities diminish and mining slows down.
Opal is Australia's national gemstone.

What is the best way to Care for Opal?

Opal Types


Black Opal Crystal Opal Boulder Opal White Opal Ethiopian Opal 

Black Opal

Black opal is the most sought after of opals especially red harlequin against a black body tone.  Black opal is not ALL BLACK but has a dark body tone ranging from N1 being the blackest.  The darker the body tone of the opal stone, the more brilliant the color and play of color can be.  Most black opals are found in Lightning Ridge, Australia which is an intriguing and very unique mining town in New South Wales.  See the selection of loose Black Opals for sale.

Crystal Opal

Crystal opal can be very translucent or ‘see through’ with some color or so full of color, you cannot see through them.  Most crystal opal stones come from Coober Pedy, South Australia and from various mines including the famous ‘Eight Mile’.  View the range of Crystal Opals for sale.

Boulder Opal

Boulder opal has an ironstone backing that was formed naturally and not attached by man.  The layer of color on top can be extremely thick and colorful to just a fine layer of some color.  Boulder opal comes from Winton and can be very large in size.  These amazing stones are making a come back in popularity and looks especially good in a custom designed setting.   See Boulder Opals for sale.

White Opals

White Opal has a ‘milky’ look to it with some color and brightness.  A white opal stone that is colorful and bright is not often found.   

Ethiopian Opal

Welo opal is from Ethiopia, Africa and is similar to crystal opal.  The intensity and depth of color in Welo opal can be mesmerizing.  Relatively new to the opal world but the interest is growing.  Is Welo opal that is black, natural Opal? While some say black Welo opal is found in it's natural form, based on our research, black Ethiopian opal is dark grey in color and fractures easy.  Ethiopian opal can be smoke treated to make it look like black opal and therefore not opal in it’s natural form. An update on black Welo Ethiopian opal: James A. emailed FlashOpal to advise there is in fact black Welo opal and provided a link to GIA - Gemmological Institute of America - where an article has been written about black Ethiopian opal. (Thank you James) This information and further information provided by James is quite interesting. - "much of this black material is not hydrophane - will not absorb water" "Also welos won over every other opal in drop test done by GIA when dropped on concrete from 4 ft, the only opals to not have any damage was welo opals" Based on this information, we obtained black Welo opal and tested it and found it to be real, natural black opal. We did not however, test the 'drop factor'. Our research will continue into this interesting gemstone. 

You will not find any doublets, triplets or synthetic opal on this website - www.flashopal.com.  You will only find genuine gems that are earth mined.

Opal Grading


How is Opal Graded?

Grading Opal by Body Tone

There is a range between N1 and N9 which determines the type of opal.  N1 being a black opal and N9 being a light opal or crystal opal.

A black opal is a natural solid gemstone with a black or nearly black body tone.  Opals in the N1 to N4 range on this scale are considered black opals - of course attracting a higher price associated with this class of opal.  That doesn't mean to say that opals in the N5 to N9 range are not worthy.  Some opals available for sale in this store are in the light opal range and due to the intensity of color, are truly worth their value. 

Grading opal gemstones requires many years of experience and being able to have the opal in hand.  Photos do not always give a true indication however a general idea can be obtained. Refer to the chart below for examples of body tone.


Opal Grading by Brightness

The brightness of the colors in an opal is very important for value and for the ‘look’ of the opal.  If the opal has dull colors, the less value the opal will be and generally not that attractive.  It may simply be a unique pattern or shape that makes it interesting.  The more brilliant the colors are in an opal, the more value the opal has.  If you have an N1 black opal with a brightness of 5, you are very lucky. 

The darker the body tone in the opal does not mean the brightness of the color will be dark.  The mere intensity of the colors can be absolutely brilliant.  Generally a white opal does not have the brightness of other types of opal stones.  On rare occasions, we do have a white opal with a brightness of 4 or more and does not stay available for purchase for a long period. 

The chart below shows the grading by brightness used on all products available in this store. Basically ONE is the least bright and FIVE is the brightest. An opal that has a FIVE with any number of plus symbols, is extremely bright. 5+++


Opal has color but is fairly dull


Opal has color but is nothing special


Opal has good color at arms length


Opal is bright and color is crisp and sharp at arms length


Opal is brilliant and color jumps out of the stone at you at arms length


Opal Grading by Pattern

The pattern or more commonly known as the ‘Play of Color’ in an opal stone is another factor in the value of an opal.  Some patterns are very rare and therefore more expensive than others.  The harlequin pattern, probably the more famous of any, is the most desired.  It is blocks of color that don’t always shine brilliant all at the same time.  There are different types of harlequin patterns such as chaff harlequin and flagstone harlequin.  Some opals have more than one pattern which is quite intriguing.

Chinese writing is another rare pattern and of course, looks like Chinese writing.  A list of patterns is below for reference.

The most important thing to remember when choosing an opal is, well of course, you must love looking at it, but out of all grading considerations, brilliance would have to be highest on the list.  Whether the opal has a brightness of 4 or 5 or ++, these opals will show their colors in any light.

The choices of colors are varied and can be a very unusual rare mix of every color, or simply one or two colors together.  Whatever color you prefer in your opal, make sure it dances for you.

Opal Pattern List:

  • Harlequin
  • Chinese
  • Mackerel
  • Pin Fire
  • Banded
  • Straw
  • Floral
  • Confetti
  • Flame
  • Roll
  • Palette
  • Ribbon

Grading Opal by Colors

Opal can have one specific color, generally green or blue, or there can be many colors or multi colors.  Colors that can be found are red, orange, yellow, gold, green, blue, purple, pink and all the various shades of these.

Red in an N1-N4 black opal is rare and expensive, especially if the brightness is a 5 or more and the pattern is harlequin.  Then you are really looking at a prized opal.  Pinks and purples are not common colors in opal but are beautiful if found together.  Again, the brightness plays an important part in how these colors show themselves.  Pastel colors are more commonly found in white opal and as the name suggests, pastel colors are not that brilliant. 

Grading Opal by Size

Is bigger best?  Not necessarily in opal.  Some small opals have the best of the above so therefore can be expensive.  The larger the opal, the rarity it will be to be a brilliant red, and you may find one here available for sale.  Opals don’t ‘come’ in all shapes and sizes as they are mined in the rough.  It is only the expert cutter who knows what to look for when seeing the rough, and then works his magic to the final stage of cutting the opal so that the end result is the best to show off the opal.

The cutter may determine an oval or round shape will do this which is the most common.  Less common is a square or rectangle shape. 

The thickness of the opal is determined by what the color band is sitting on or formed on.  If this is stable, it will be left and you have a thicker opal.  If it is more sand like, then the opal will not be as thick.  Most of these pieces are used for inlay jewelry. 

Free form opal is generally larger opal or pieces that are too exquisite to be cut any further or are interesting enough as they are in their natural state.  These can make great one off designer pieces of jewelry which we would be honored to make for you.

Thicker opal is recommended for prong set as the opal would be stronger and stable for long wearing.

Of course, it is the natural formation over millions of years that opal exists.  Therefore, we cannot simply 'order up' an opal of choice.  As no two opals are the same, no matter which opal you have, you have a truly unique piece.