Customer support Message Us

Delivery Info

Delivery Info

All goods shipped are insured against loss and damage whilst they are in transit.

Once you are advised by e-mail that your order has been shipped, we guarantee delivery of all items except in cases where the address supplied is incorrect, illegible, incomplete or if the recipient is away or has moved, in which case you will be liable for payment of the purchase price and shipping of the order irrespective of whether the order arrives on time or not at all.

Free Returns

Free Returns

Gillett's Jewellers are committed to the provision of high quality products. Guarantee: We guarantee that our products will be delivered in new condition without damage or fault in craftsmanship.

If the product was damaged or faulty in its craftsmanship at the time of delivery to you (the customer), you may return the product within 30 days (of the delivery date) and Gillett's will refund the product price or replace the item.*

Free Shipping

Free Returns

Gilletts Jewellers offer free shipping for items over the value of $100.



You have no items in your shopping cart.


Become a Member for free

Opal Jewellery Advice

Opal jewelry information including advice about choosing opals, buying opals, opal types and caring for opals. This opal advice also includes opal jewelry information about black opal, crystal opal, solid opal, doublet opal, opal inlay and other opal jewelry.

Opals are one of the world's most beautiful gems. The most appealing aspect of Opals is their vast array of colors and patterns. Opals, more so than any other gem, come in varying colors, qualities and types. To help understand what type of Opal is best for you, have a look at the following information about Opals.

Where does Opal come from?

Over 90% of the world's supplies of Opals come from Australia.
  • Black Opals come from mainly from Lightning Ridge (New South Wales - Australia)
  • Boulder Opal comes mainly from Quilpie (Queensland, Australia)
  • Crystal & White/Milk Opal comes mainly from Coober Pedy & Mintabie (South Australia)

What is Opal?

Opal is made from small silica spheres arranged in a regular pattern. The type of silica in Opals is chemically similar to quartz, but Opal silica contains water within the mineral structure. Precious Opal generally contains about 6-10% water. The vast number of colors in Opals are caused by the regular array of silica spheres diffracting white light, and breaking the light into the colors of the light spectrum. The actual range of color in a particular Opal is determined by the diameter and spacing of its silica spheres. The colors of an Opal can also change depending upon the angle of light incidence, so when an Opal is rotated, its color can change or disappear. This feature makes Opals extremely interesting and unique.

Types of Opal

Solid black Opal

Black opal pendant Gillett's black Opal products

There are four main types of precious Opal - Black, Crystal, Boulder and White/Milk. When used in jewelry, in addition to the type of Opal, there are solid, inlay, doublet and triplet Opals to choose from. Each of these types of Opals are discussed below.

Black Opal

Black Opal is considered the most valuable and expensive of Opals. It has a dark background color when viewed from above. Black opal stones that have a dominance of intense red color are the most expensive. The brighter and sharper the colors, the more valuable the Opal. Click here to see Gilletts black Opal jewelry
White gold crystal Opal earrings

Crystal Opal

Crystal Opal is transparent or extremely translucent and has a variety of diffracted colors. As crystal Opal is transparent, a black backing can be placed behind the Opal to allow the bright natural colors of the Opal to appear. Some of the most appealing Opals are crystal Opals. We offer many crystal Opals for their variety of sublte colors.

Boulder Opal

Boulder Opal is a solid Opal which consists of a fine layer of natural Opal which has formed naturally on ironstone rock. Boulder Opal from Queensland is declared by many experts to have the most brightness and best appearance of the Australian Opals.
Milky Opal ring

White or Milky Opal

White or Milky Opal is the most common of all Opal. It has a light or pale background and often displays red, green and blue pinfire.
Solid Opal ring

Solid Opal

Solid Opals are one piece of solid Opal which are cut with a smooth rounded surface (Cabochon cut) rather than a faceted surface. Solid Opals are generally more valuable and expensive than doublet and triplet Opals as they contain a higher carat weight of Opal.
Opal inlay pendant

Inlay Opal

Inlaid Opals are solid Opals which have been inserted into a piece of jewelry so that the jewelry metal surface is level with the surface of the Opal. Inlaid Opal can be any type of Opal, but we usually prefer Black, Crystal or Boulder Opal inlay.
Opal doublet ring

Doublet Opal

Doublet Opals are Opals which when found are not thick enough to be cut as solid Opals. Our doublet Opals are made using a layer of colorful precious Opal with either common Opal (less colorful) or ironstone (the stone in which Opal is found) attached to the back. We mainly use boulder doublet Opals, because Boulder Opals are extremely bright, attractive and offer a wide variety of colors. Boulder Opal also naturally occurs in thin layers attached to ironstone. Good doublet Opals are very colorful and appealing and are a great alternative for people looking for an attractive piece of Opal jewelry without spending the price demanded by solid Opals.


Triplet Opal consists of three layers, a thin layer of precious Opal, a thicker quartz layer placed on top of the Opal, and an ironstone or common Opal back. As triplet Opals consist of the least carat weight of Opal they are generally priced significantly lower than solid and doublet Opals. We generally prefer to offer only solid and doublet Opals for their higher quality.

What to look for when buying Opal jewelry

Opal inlay ring

When buying your Opal or Opal jewelry you should first consider the combination of the Opal's type, size, brilliance, color and pattern. As with any gems, there are trade offs that have to be made, and once you choose the type and quality of Opal, it usually comes down to simply choosing a color of Opal that you find attractive and that meets your budget. Click here to see Gillett's Opal jewelry.

Type & Background color : The type and size of Opal are the primary factors in determining the value of Opals. Gem quality black Opal commands the highest prices per carat weight. Black Opal, which has a dark background, is more valuable than crystal Opal, which in turn is generally more valuable than white/milky Opal.

Size : With all other factors held constant, the larger the Opal the more valuable. As with other gems such as diamonds and sapphires, Opals are measured in carats.

Brilliance: The degree of brightness is of paramount importance. The more vibrant the colors in an Opal, the greater its value will be. A dull stone with many or all colors will be less valuable than an Opal with a single, vibrant color.

Color : Generally, the more colors in an Opal the more valuable. The dominant colors of fire in an Opal have value in the order of red, orange yellow, green, blue, indigo and violet.

Pattern : good patterns of colors together with brilliance have a large effect on the value and appeal of Opals. Broad patterns or large flashes are more valuable than pinfire and small types of pattern. Distinct patterns such as harlequin, rolling flash, jigsaw, block and ribbon are very rare. Again, in the end it comes down to what you find appealing. Click here to see Gilletts Opal jewelry.

How to care for your Opal

Boulder doublet earrings Gillett's Opal earrings
Opals are more delicate than other gems like diamonds and sapphires. They require a little more care and tender treatment when worn. It?s best and we highly recommend that you remove your Opal jewelry when playing sport, gardening and performing household tasks like washing dishes and showering. Try to avoid knocking or scraping your Opal as this may damage it. Due to it?s delicate nature we do not recommend that Opal jewelry, particularly Opal rings be worn every day. Although you may choose to, we do not recommend and would tend to discourage Opal rings being worn as Engagement or Wedding rings simply because they are not nearly as hard as diamonds and sapphires and they are more prone to damage from everyday knocking or scratching. Opal rings are best worn as dress rings for wear when you go out rather than for every day wear and wear around the house.

How to clean your Opal jewelry

To clean the surface of your Opal it's best to softly rub the Opal with a facial tissue or piece of silk. Do not use chemicals, abrasives, toothpaste or ultrasonic cleaners to clean Opals. A mild soapy luke-warm water solution and a very soft toothbrush may be used for jewelry set with solid Opals, but it is best not to immerse doublets Opals or triplets in water as the ironstone adhesive may deteriorate. Opals may be damaged by sudden severe temperature changes, such as when wearing an Opal ring whilst cleaning dishes. For this reason it's best not to wear Opals when cleaning dishes or showering.

Please wait...

You have added the following item to your cart:

You have no items in your shopping cart.