October Birthstone – Opal

A polished oval-shaped Boulder Opal gemstone

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The October Birthstone Opal

Happy Birthday to all those October babies out there!

As we head into the tenth month of the year, we get to celebrate the October birthstones, which are none other than the beautiful Opal & Tourmaline.

In this blog, we look at one of these gemstones – the October birthstone Opal. 

Opals are also the stone used to celebrate a 14th Wedding Anniversary.

The Opal gemstone has a wonderful mix of colours within it.  It seems to contain the entire spectrum inside the one stone and is quite mesmerising to look at. 

We look at how it is formed and where it is formed.  We’ll take a look a the different types of Opal.  What does an Opal symbolise?

Something that everyone seems to think they know about … the superstitions surrounding Opal which, as it turns out, were never true. These superstitions have deterred people from wearing opal jewellery, which is such a shame as these rumours seemed to be mistruths. 

In fact, you could say that this beautiful gemstone has had the worse rap of all the gemstones.  Prepare to be surprised!  

We will also cover the healing powers some believes it possesses.

Table of Contents

Properties of Opals

What is an Opal Made Of?

Opal is made of silicon dioxide and water. 

An Opal forms when a combination of Silica and water flows into cracks and spaces in the ground. This gradually hardens and solidifies to form Opal.

As this gemstone contains water (up to 20%!) it makes it very sensitive to heat.

Opal & Pearl Blossom Earrings - Q P Jewellers
Opal & Pearl Blossom Pendant - Q P Jewellers

Where are Opals Formed and Found?

It is mined in Australia, Ethiopia, Mexico and the U.S. 

The stone is formed in dry regions, such as Australia’s semi-desert conditions.  Australia supplies approximately 80% of the worlds opals, centred around a town called Coober Peby some 430 miles south of Alice Springs. 

Opal is actually the national gemstone for Australia.

How is Opal Formed?

Opals are formed in very dry, hot areas.  When the rains come the rainwater soaks into the deep underground rock through the cracks in the ground, carrying silica, which has been dissolved in the rain, downward.

The drier periods arrive and the water evaporates leaving behind deposits of silica in the cracks of the rocks and it is these deposits that form Opal.

Oval Opal Studs in Gold - Gemondo
double opal drop earrings
Double Opal Drop Earrings - Gemondo

The Five Main Opal Colours

Three Black Australian Opals
Black Autstralian Opals. Source: Deposit Photos

The Opal can be found in different varieties of colours. The five most common colours are White, Black, Fire, Boulder and Crystal.

The most common is the “White Opal” or Light Opal, which isn’t just white. This fabulous stone has a white or translucent to semi-translucent body colour and contains hints of pastel rainbow colours.

Another popular Opal is the “Black Opal”, this can vary in body colour from either black, blue, or grey. Translucent or opaque with a play-of-colour against a black or dark background.

Fire Opal has a translucent with red, orange, brown or yellow colourings and sometimes called Mexican Opal.

Boulder Opal is translucent with a variety of colours with the surrounding rock becoming part of the gemstone.

Crystal or Water Opal is transparent with a clear background and an exceptional play of colour.

18ct gold pendant with oblong opal gemstone on gold chain
18ct Gold Opal Diamond Oblong Pendant - C W Sellors

The History of Opal

In ancient Arabia, they believed it that Opals fell from the heavens in flashes of lightning.

Shakespeare said of Opal, “that miracle and queen of gems”. 

In England Opals were called “Ophals”, short for ophthalmos, referring to the human eye.

But the name Opal originates from the Latin “Opalus” from the Sanskrit Upala meaning “precious stone”.

The Word ‘Opal’ also means to see a change in colour.

Every Opal is unique and this marvellous precious stone contains many colours. 

gold oval drop earrings with opal and diamonds
Gold Oval Cluster Drop Earrings with Opal & Sapphires

Two Classes of Opal

There are two main classes of Opal – Precious Opal and Common Opal.  

The thing that differentiates the two is something called ‘Play-of-Light’ which basically means iridescence.  Precious Opal has iridescence – meaning it displays many colours as if diffuses light.

Common Opal does not have any play-of-light. 

The Play-of-Light of in Precious Opals

Sample of boulder opal
Boulder Opal Sample

The spheres that make up the gemstone to produce Opal means the light bends as it travels through the stone. It is this that gives the rainbow-like colours, called spectral colours. 

The different-sized spheres determine what colour you will see – red is produced with spheres which are 0.2 microns in size; violet is produced by spheres 0.1 microns in size.

The play of light and fabulous colours in opal make it perfect for using in jewellery designs like the Evil Eye symbol. 

Positive Meanings Associated with Opal

18ct gold necklace with opal stone entwined in gold
Pink Opal & Pink Sapphire Drop Earrings with Diamonds

As early as man has used gemstones they have attached meanings to the stones. There are many positive assertions about this beautiful gemstone. 

Gemstones were carried as talismans and later incorporated into costumes and jewellery. In earlier times they were adorned to sheaths of weapons (for instance, in going into battle), often because of the meanings and the power they were believed to hold.

Early people credited Opal with magical powers and they said they would bestow the wearer with luck and many possibilities. 

Roman Emperors gave their wives Opals for good luck. They believed that the myriad of colours was like a rainbow and would bring its wearer good luck and prosperity.

The Romans prized the gemstone second only to emerald. They believed it to have a beneficial effect on peoples eyesight, to banish evil and brought hope and purity to the wearer.

The Opal symbolises faithfulness, loyalty, happiness and purity, the list goes on and on. If the more esoteric qualities of stones attract your attention, the Opal can be beneficial for the eyesight, hair, nails and skin.

Many years ago that necklaces would be worn to repel evil spirits and protect the eyesight.

Mothers would hang Opal jewellery around their children or have an Opal stone somewhere in the house to give them protection.

Napoleon gave Josephine a large red opal called “The Burning of Troy”.

Queen Victoria loved Opals and did a lot to rid the gemstone of its bad press, which we will talk about next. She wore them throughout her reign

white gold oval opal and diamond cluster ring
Oval Opal Halo Ring with Diamonds

Superstition About Opal

Is it true that opals bring bad luck? Just what are the superstitions surrounding Opal? 

Sadly this gemstone seems to have had its fair share of negative press associated with it. This was particularly so around Europe and the Middle East (and we will explain why later).

There has perhaps been no other gemstone that has had such a level of superstitious ignorance railed against it.

Alarmingly, Diamond traders may have contributed to some of these superstitions as the beautiful Opal gained in popularity and competed with their diamond market. This was particularly when the high-quality Australian opals began to appear on the market in the 1890’s. 

opal earrings gold rope edging
Gold Round Opal Earrings with Rope Effect Edging

Opal is a Soft Gemstone

Just when you thought it couldn’t get any worse for Opal, it does. 

Opal is a fairly soft stone – it measures 5 to 6.5 on the Moh’s Hardness Scale. 

This means that it is not an easy stone to cut and set as it is easily fractured when worked. 

The gem-setters were often left in the unenviable position of having to explain to their masters that the stone had been ruined whilst attempting to cut and set it.

Louis XI was so angry with his goldsmith when one of his opals was damaged that he had the poor goldsmith’s hands cut off!

Not surprisingly, gem-setters also began to dread the stone being brought to them and avoided working with it.

As I’m sure you will agree, this beautiful gemstone has had such a bad rap and been incredibly misunderstood, if a gemstone can be misunderstood!

The Fortune of Opal Today

heart shaped oval pendant encased in gold
Heart Opal Pendant Encased in Gold

The fortune of Opal is on the turn again, though and there is a “booming demand for opals” as documented by this BBC business report.

Global prices of opals have doubled in the last few years, as there has been an increased demand from China, India and a revival of interest in the West.

A few years ago Vogue featured young jewellery designers who were using opals in their designs and Dior featured a jewellery collection with Opal as the central gemstone in the collection.

Traditionally you rarely find Opal set in silver, it is mainly set in gold, however we do have some pieces of silver jewellery set with Opal.

A few pieces of Precious Opal gemstone on a black background
Precious Opal. Source: Deposit Photos

Synthetic Opals and Simulant Opals

Synthetic opal, which has the same chemical composition as natural opal, is man-made.  The difference (which can be spotted with a jewellers loupe) is that the synthetic opal which has a more regular pattern to the structure.  As they are grown in the lab they will build layers on top of each other and so regular columns are formed. 

Opal Auctions, in Australia, who have a wealth of information about opals, produced this fascinating video which demonstrates how to spot a synthetic and simulant opal. 

Real opal has an irregular pattern – hence the wonderful flashes of light.

Just because it is synthetic, it doesn’t mean that this man-made opal will be cheap.  You can find many pieces of jewellery set with synthetic opal and they can still look stunning and demand a good price.

Simulant opals can be made of anything, for instance, glass but are just made to look like opal. These are called Opalite.  This is flawless, but you won’t get the play of colour and it is in no way natural.


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Silver Hoop Earrings with Opalite

Opalite is a man-made glass stone  used in jewellery making – these stones also seem to take on a luminous, blue glow as does a genuine opal and they look fabulous in silver jewellery, creating lovely flashes of light when worn, although you won’t get the play-of-colour that a natural, real opal gives.   

Caring For Opals

You need to take particular care of opal gemstones.  They are quite porous and will absorb many chemical cleaners, which should be avoided at all costs. 

Likewise, no abrasives should be used (no toothpaste – and that includes for the rest of your jewellery, but particularly opals).

Use warm soapy solution and a soft brush or cloth (a soft makeup brush will work well).  Never use water with opal doublets or triplets because it could dissolve any glue used between the layers. 

A jewellery cleaning solution which is gentle enough for opals are the Connoisseurs Delicate Jewellery Cleaner of their Cleaning Foam. 


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