Australian Opal Gallery
EST.1964
WHAT IS AN OPAL ?
The name opal is derived from the Sunskrit word “upala” meaning “valuable or precious stone”. The world famous opal scientist Paul B. Downing PhD referred to opal as “the most interesting and unique gem in the world”. About opal he said: “It can have all the colors of the rainbow… the red of ruby, the blue of the sapphire, the green of the emerald, and all other hues in vibrant to pastel shades”. What at amazing and unique gem! In opal you find the combined beauty of many precious stones! Lovely colors flash and change in a myriad of patterns as the stone is moved around. What could be better?
Technically opal is a non-crystalline form of the mineral silica or hydrous silicone dioxide. Despite its amorphous structure, opal displays an amazing degree of internal organization in a rigid gel form. Its water content is about 5-9%. It is similar to quartz and amethyst. Opals are a relatively soft stone rating around 5.5 to 6.5 on the Mohs scale of hardness. As a comparison, diamonds rate around 10, sapphires around 9, quartz is around 7, and pearls are between 3 and 4.
Color and Fire in Opals
Opal derives its colors in the same way as the rainbow. It is made up of billions of closely packed spherical particles of amorphous silica stacked in three-dimensional grafting. Depending on their size, when light passes through these spheres it is diffracted into wavelengths of different colors. These spheres are so small that two capped hands would hold more than all the grains of sand on Boni Beach in Australia. To cross the smallest dot of a ballpoint pen it requires 20,000 or more of them.
When the tiny spheres of silica settle into a very regular lattice-like structure something magical happens. Light entering the opal is sent back out of the stone in a process called diffraction. The silica balls break up the light into the colors of the rainbow. When this happens, the opal is said to have a play of color or fire. It is only those stones which have this fire that are considered gem or precious opals. It is fascinating that the colors in opal are produced purely by light. This is similar to how a prism breaks up white light into all the colors of the rainbow. While a prism is a different process than diffraction, the end result of both is a beautiful array of colors.
An opal may have all the colors of a rainbow or in rare cases just one. The color or colors produced depend on the size and consistency of the silica spheres in the opal. Take an opal in your hand and play with it. As you move the stone, notice how the colors change. A color will appear then disappear. In another spot a color may change from blue to green to red. What is happening is that the light is hitting the lattice-like structure of the opal from a different angle. This is how different parts of the rainbow spectrum can be seen.
How are Opals judged?
Opals are judge on the same criteria as diamonds: color, clarity, carat weight, and shape. (For weight, five carats equals one gram.) Within these parameters are many types, forms, grades, and sizes – each with their own individual beauty and value. Color is a matter of choice with red being most valuable followed by orange, green, blue, and purple. Man in his ingenious way, has extended the appeal for this magnificent stone by making doublets and triplets. Opal is the only gem on earth that diffracts white light or sunlight into different colors – this phenomenon makes it one of the most sought-after gemstones in the world!
HOW WERE OPALS FORMED ?
Many years ago during the Cretaceous period, central Australia was covered by a giant inland sea. As the inland sea retreated, silica rich sand were deposited onto what is now basically a desert area. Weather conditions changed the sand sediments and released large quantities of soluble silica creating a gel. This gel seeped into cracks and crevices in the ground and gradually hardened through nature's heating and molding processes resulting in the creation of opal.
WHERE DO OPALS COME FROM ?
Common opal is found in a limited number of countries. A small amount of precious Opal is found in Brazil, Mexico and the United States - Nevada, Oregon, and Idaho. Recent discovery of opal in Ethiopia is slowly reaching the market. Canada now produces gem opal from a mine in Vernon, British Columbia. However, 90% of the world’s precious opal comes from three isolated areas in the outback of Australia.
Australian opals can easily be distinguished by their brilliance and play of color. In Australia, Black opal comes from Lightning Ridge in New South Wales, while Light or white opal is mined principally from the South Australian fields of Mintabie, Coober Pedy and Andamooka. Boulder Opal is from Central Queensland in the areas surrounding the townships of Quilpie and Winton. These opal fields of Australia are in the harsh outback where only the hardened miner can make a living. In Coober Pedy miners liveunderground to escape the extraordinary heat and relentless dust.
Where and When were Opals Discovered?
The first precious opal in recorded history was reported during Roman Times. This highly valued and very rare gem was discovered in Pannonia an ancient province of the Roman Empire in the area where Hungary is today. Opal gained prominence in the jewelry industry in the late 1800's. Precious opal had been discovered in several areas of Australia. A gentleman named Tully Wollaston brought Australian opal to the gem industry in London. While it took a bit of time for buyers to accept the stone, once accepted its popularity not only grew rapidly but exploded everywhere. New discoveries throughout the 1900's have made Australia the primary source for the opal now found in the marketplace.
TYPES OF OPALS
Andamooka Matrix: Andamooka is not only famous for
its brilliant crystal opal but also its beautiful dyed matrix. Normal
opal cannot be dyed, as it’s too impervious. However, Andamooka
matrix is a porous form of quartzsite in which opal has grown. Its
porosity allows the penetration of carbon to be placed between
the opal and the rock, which is then polished to enhance the gem.
Good gems can demand high prices and look extremely attractive.
Matrix Opal: The matrix is manifested in two basic forms: Boulder Matrix and Andamooka Matrix.
Boulder Matrix: There two main varieties of boulder matrix are
found on almost all Queensland opal fields. Literally, matrix means
“surrounded by” and that’s what it is: a beautiful pieces of sparkling
opal surrounded by ironstone. In stones from the northern fields
around Opalton, most of the rivulets of color are like long flowing
streaks of lightning that change with the slightest movement.
On the southern fields, the well-known hook like design of color
create the legendary Yowah and Koroit matrix.
Solid Light Opal: Coober Pedy is the main source of Australian light opal.
Discovered in 1915, it is the world’s largest opal field. The color saturation of
these opals can vary greatly from bright crystal to milky gray. The brightness and clarity of the stone, along with its color and pattern will determine its price.
The price range is from $90 - $1,200 / carat
Solid Crystal Opal: The term crystal refers only to the clarity of the
gem not its micro-structure. Almost all crystal opals have no potch
backing (mineraloid that precious opal is formed on) and when held up to the light are translucent. They range in color from black to almost glass-like and are found in Australian fields. The crystal opal capital of the world in Andamooka. The price range is from $110 - $1400 / carat
Boulder Opal: Like the solid black opals of Lightning Ridge, boulder
opals have a natural back but this time it is ironstone. Many of these
beautiful gems have an undulating face allowing them to be cut into
free forms of stark beauty.
The price range from: $90 - $100,000 / carat
Solid Black Opal: A solid black opal is a natural stone that has grown
on dark potch matrix, which can range in color from black to grey. Some
of these gems may carry small inclusions or sandpits, which does not
devalue the stone and are often the hallmark of the genuine article.
The black opal is the most valuable and rarest of all.
The price range from $450 - $25,000 / carat
SOLID, DOUBLETS, AND TRIPLETS
Amazing patterns of Australian Opals !
Ironstone or
Solid Opal
Opal Layer
Opal Layer
Ironstone or
Acrylic Layer
Opal Layer
Precious Metal
Boulder Stone
Boulder Stone
Solid Opal - Solid opal can be cut into many shapes.
Unlike diamonds and other precious gemstones, it is not
cut into facets because this would spoil the play of color
with reflections. Usually it is cut into a softly curved
cabochon or into beds, cameos, and various free
form shapes.
Doublets - Around the doublets there are lots of myths an misconception going around in recent years. Here is the real truth about the doublets. Doublets are two pieces cemented together bonding a layer of precious high-grade crystal opal
(in many cases resembling fine quality black opal) with genuine
Australian boulder or ironstone back. This not only protects the opal but also enhances the color making the opal very attractive at an affordable price! Thus the beauty of the precious opal is made available to anyone!
Next time when someone, even a jeweler tries to tell you that
doublets don't hold real value, you will know that this is
not true at all. Doublets are made from real organic precious opal and genuine Australian boulder stone. Certainly, they are worthy of a place in any good gem collection. In today's market a good quality doublet goes for between $90 - $120 dollars per/ carat.
Triplet - Triplets are doublets with clear domed caps
cemented to their faces. The hardness of the cap used may
vary from glass to quartz depending on the quality of the opal.
The domed cap protects the opal and magnifies the pattern, greatly enhancing the overall appearance.
Solid Inlay - Solid inlay is a relatively new innovation in the manufacturing of opal. Using light crystal opal the stone is
cut to fit the jewelry setting. The opal is than bonded and polished into the jewelry allowing the skilled jewelers
to make the opal follow the contours of the piece. Like a
doublet, solid inlay enhances and protects the beauty
of the opal.
There are several different ways in which opal is presented loose in its finished form or set into jewelry. It is important to understand the different methods in order to fully understand the range of jewelry from Australia.
Most Opals (at least 80-85%) have a pattern that fits into the flash fire or broad flash fire category. Despite most of the attention paid to pattern, it like fire, color, has far less influence on price than commonly believed. Value can significantly affect by the unusual patterns like the harlequin and other rarities. The fire pattern is created by the play of color in the stone. Patterns are infinitely variable and no two are ever exactly alike. For whatever reason, people just love to make up names about the patterns: ocean mist, midnight blue, rainbow, fireworks, exploding fire just to name a few. However, there are generally five basic categories. Let us introduce them.
Pin-fire:
Small pinpoint circles of fire. When viewed from the side this pattern often looks like the side of a stack of pins, while the top view looks like the points of those pins, hence the name. The side view is called columnar fire. This is actually a fairly rare pattern. Many small flash-fire pattern stones are incorrectly identified as pin-fire.
Flash fire:
Irregular splashes of fire covering the stone. The splashes of fire can be fairly large but
not one area would cover more than 50% of the surface of the opal.
Broad Flash fire:
Sheets of color usually covering a large section or the entire surface of the stone.
Rolling Flash fire:
Sheets of color which roll across the surface of the stone as it is moved. This type of
pattern is highly prized.
Harlequin:
Square or angular blocks of fire set closely together. True harlequin is very rare and extremely valuable.
Rare patterns: Rare and unusual patterns that are not regular are also especially valued, but not true harlequins.
Unusual and Unique Patterns
There are some stones that will combine several beautiful patterns into one. Now you know this incredible gem has many patterns and colors like a rainbow that make it superior in the Gem World. One can delight in these beautiful colors and varieties of patterns and if desired can be the lucky owner of a magnificent piece of jewelry. Each pattern will enhance the occasion you choose to wear it to!
Ribbon pattern
Peacock pattern
Floral pattern
Chinese writing
Chaff pattern
Flagstone pattern
Straw pattern
Fern leaf pattern
Abstract pattern
Palette pattern
Windmill pattern
Flame pattern
LOOKING AFTER YOUR OPAL
Although opal is a magnificent and unique gem, it does not have the resistance to breaking or scratching that diamonds or sapphires have. If you protect the stone from heavy blows and abrasive materials, and don’t subject it to extreme sudden heat changes, the gem will last forever.
To ensure you are rewarded with a lifetime of joy of wearing one of nature’s most beautiful gemstones, please follow the instructions below:
To prevent build-up of grime, remove your opal jewelry when washing dishes (in case of a ring), showering or swimming.
Avoid chemicals which may cause discoloration or damage to your opal for example dish washing liquid, chlorine, and perfume.
Avoid excessive exposure to water when wearing doublets or triplets. Hand washing is acceptable.
Use a clean cloth to polish our jewelry in particular the doublet range. If overtime the piece needs professional re-polishing, only use a jeweler or polisher experienced in opal.
Avoid extreme changes in temperature, direct heat, and don't leave opal jewelry in direct sunlight for a long period of time.
Avoid dropping or knocking your opal product on hard surfaces.
If your opal is being kept in a safe for prolonged periods of time, place a small container of water in the safe along with your opal to ensure humidity is present. Alternatively you can wrap the piece in damp cotton wool and place it in a sealed plastic bag.
Treat your opal with care like any precious gemstones such as the emerald and pearl.