Above Ground Boulder Opal Mining

Above Ground Boulder Opal Mining
Above Ground Boulder Opal Mining

Sunday, September 26, 2010

Care and Myths about Opals

There seems to be much confusion about the proper way to care for and clean opals. Here is a simple guide that will let you preserve your beautiful opals and keep them looking their best.

To care for Opal correctly, two of the basic physical properties of this unique and beautiful gemstone must be understood.Precious Opal contains around 6%-10% water (sometimes higher). Opal has a hardness of 5.5 - 6.5 on the "Mohs" scale of hardness. First and foremost you must determine if your opal is a natural occurring solid, doublet or triplet. The care instructions for each differs significantly.

When purchasing Opal, buy quality -stones only from knowledgeable dealers or jewelers . It's important to find someone who understands Opal and can offer you the right care advice for a particular Opal. If you know precisely the type of Opal you have purchased, you will know how to care for it.

Can I put Opals in water?

Yes!
Clean temperate water will in no way harm a solid Opal, in fact it is highly recommended “Solid” Precious Opal should be placed in a dish of clean room temperature water for at least 10 - 15 minutes, every 12 months or so. From personal experience (gained from over 27 years of cutting, collecting and handling opals) this allows the gemstone to absorb any moisture it may require therefore preventing any crazing or cracking caused by drying out. (Especially if the opal has been subjected to harsh or dry conditions).

Basic Care Practices

Always remove rings when "Washing Up". Even solid Opals can be adversely affected if subjected to sudden temperature changes. (Such as being placed in very hot water). If the stone is an opal doublet or triplet, it is unwise to place it in water (particularly hot water with detergent, as in washing up) for any length of time as it may affect the cement that is used to bond the stone segments together (Doublet - 2, Triplet - 3).

Do not wear OPAL when gardening.

Sand or soil is abrasive and will wear the polish off the stone over time. Also there is the chance, if you are doing any sort of work that could bring the stone in contact with hard surfaces, a flick of the wrist in the wrong direction could chip it.

How do oily substances affect an opal?

It is recommended you do not place Opal near oils or oily substances, however oily hand and face creams will usually not damage Opal. (Except that they may "build up" around a ring and make it look unsightly.)

How do I store Opals for long periods of time?

De-humidified atmospheres, (such as bank vaults and safety deposit boxes) are to be treated with caution when storing Opals for prolonged periods, as they can extract the water content from an Opal over time, which may cause the Opal to crack or craze. If Opal must be stored in these conditions, it is strongly advised to put them in a sealed plastic bag or container with a little water to prevent drying out.

Also it is advisable to check your Opal every 6 - 12 months to ensure it has not "dried out". Otherwise, it is generally safe to store them away, as long as the area is not overheated.

Displaying Opal

Don't store Opal for prolonged periods of time under hot lights, as this could crack the stones if the heat builds up and is magnified. (As in many showcases). If Opal is to be displayed under these conditions it is strongly advised to place the Opal in or near a source of moisture (i.e.; a bowl of clean water or wet sponge).

Cleaning Opal

nt) in lukewarm water using a cloth or soft brush. After cleaning, Opal should be rinsed in clean room temperature water.

By following these few simple rules on basic Opal care; your Opals will last forever as a source of enjoyment and natural beauty.

More to come.....

See some of my opals here Boulder Opals

Types Of Opals


Black/Dark Opals

Black/dark opal shows a play of colour within or on a dark body tone, while the play of colour of a black opal is within or on a black body tone, when viewed from the face up. It can be crystal or opaque. Some black/dark opals have a light crystal colour bar on dark opal potch (colourless opal), giving the otherwise light opal a dark appearance. Even expensive black/dark opals may have only a very thin colour bar on black potch.

Most black/dark opal is found in the mines around Lightning Ridge, NSW. Because of its relative scarcity compared to light and even boulder opal, it tends to be more expensive, given equivalentcolors, clarity and patterns. Black/dark opal exhibiting bright flashes of red is extremely rare.

Boulder Opals


Boulder is a variety of precious opal which has an ironstone host rock bonded naturally to the gem. Often just a thin vein of precious opal is present. It occurs in specific locations over a wide area of Queensland where the opal fills cracks or voids in ironstone boulders. Boulder opal can be black, dark or light depending on the appearance of the stone when viewing the presentation face.

Matrix Opals

The term matrix opal is commonly used where the opal is intimately diffused as infillings of pores or holes between grains of the host rock in which it was formed. Andamooka matrix opal is a porous material from Andamooka, South Australia, which is often treated to enhance thecolor by depositing black carbon by chemical treatment in the pore spaces in the stone.

Doublets and Triplets

A doublet is composed of two sections, with a thin slice of opal comprising the top portion. Natural opal is fused to a black stone backing, leaving only the color of the opal visible

A triplet opal is so named because it has three components: a thin slice of crystal opal sandwiched between a clear top and a black backing. The top is quartz or glass while the backing can be black non gem quality opal or manmade resin.

More to come.....

See some of my opals here Boulder Opals

Where does Opal Come From?

See My Photos of this trip here

AUSTRALIA, the lucky country, was blessed when nature chose her as the host for the world's richest reserves of the most beautiful gem on Earth, Opal. With the exception of a few isolated pockets around the coastal regions, all of Australia's commercial opal is found in the inland desert areas. It occurs west of the Great Dividing Range over an area of approximately 500,000 square kilometers stretching well into the state of Western Australia. Most of the well-known reserves are located in South Australia, New South Wales and Queensland.

Except for a very small percentage of volcanic opal, Australia's commercial opal is found in cretaceous (about 140 million years ago) sedimentary rock formations. This is true for the fields in NSW and South Australia. However, in Queensland the opal can often be much younger coming in the Eocene or tertiary age. Geologically, this is recognized as being the period from about 65 million years ago. So the Queensland opal geology is different to the others in Australia. It is different because of the type of parent material in which it was formed. The very beautiful Queensland variety is generally known as Boulder Opal.


More to come.....

Mining Boulder Opal In Australia

One of the first impressions I had was how barren the middle of Queensland, Australia was. During the 14 hour drive out to the mining site, you see very little once you head about an hour or two West out of Mackay. Winton is the closest town to the mining site, and it will be 4 hours away. Winton is a lovely town of about 950 people.
Everything is Australia is on a grand scale. You see cattle farms, that as you drive by at 60 mph that go on for hours, hundreds of square miles in size. The only other thing you see are kangaroos. Very surprised by the size of some of the kangaroos, some 6-7-8 feet tall. Most vehicles in this area seem to be equipped with Kangaroo guards on the bumpers, and extra gas tanks as once you get in the Outback, there is no place to fill up.
Once we arrived at the mining site, you see the lifestyle. About 30 people who mine opal have formed a small community and they are completely independent from the world, cell phones don't work, only electric is if you have a generator, mail delivery twice a week, you have a water tank that collects water, and the homes I would describe as if a trailer and a tent had a child, this is what they would produce.

That first night the 30 something group held a BBQ in my honor. They set a BBQ fire going larger than any I had ever seen, it had to be 200 feet across, and got to meet everyone that first night. Being from New York, I was amazed by the sky. I'm so used to have the light pollution of a normal city hiding the stars, but here you don't find that. You can see every constellation in the sky in all their natural elegance.
Life here is hard, during the summer months temperatures can reach 99 degrees Fahrenheit (37 Celsius) with lows around 77 degrees Fahrenheit (25 degrees Celsius), they tell me during the summer months, you always want to wear gloves as you can burn your hands just touching a rock. Mining is generally halted in the summer as its too hot, and even during the winter many miners I met work 5 or 6 hours a day because of the extreme conditions.
More to come.....