Opal is a fascinating stone, but of all precious stones, is certainly the most difficult to choose to be mounted on a jewel.

It's indeed complicated to give a physical description of the opals as they vary in color, transparency and reflections depending on the country of origin and often same, vary greatly depending on the extraction mine.

Unlike a ruby or a diamond for which it's easy to compare prices according to some criteria (the famous 4Cs of diamond), all opal stones are unique in their colors and light effects.

So you have to find the jewel with opal that suits you best by comparing the stones at your disposal according to your budget.

Opals from Australia

Diversity of opals is blatant in these two photos

Above, noble opals from Australia and below we can see Mexican opals white, transparent and fire opals with and without play of light.

Opals in Mexico

Mexican fire opals 

Their composition makes them very delicate to cut and fragile when they are worn on rings or bracelets which are jewels most exposed to blows.

This article aims to guide you in your choice of stone by presenting you all the useful information to create your jewelry with opals.

Noble opal ring Gold opal ring

Index

  1. Composition and origins of opals
  2. Opal frames on jewels
  3. Maintains opal stones
  4. How to choose the opal of his jewel

Composition and origins of opals

Opals are not crystals, but amorphous silica containing a variable part of water. It is the spheres of silica that diffract the light are responsible for light effects of noble opals.

Their general color varies enormously according to their composition and therefore according to the nature of the soil where they were formed.

Unlike other precious stones, which are highlighted when the light passes through them, the opals can be opaque and nevertheless present exceptional color reflections, resulting from the diffraction of the incident light.

So we often find beautiful opals on jewelery in the form of cabochons set in a closed setting.

Opals can be opaque or translucent, black, white or red and may or may not have light effects.

Mexican fire opal

Mexican fire opal from the Magdalena de los opalos mine

Here are the different types of opals that may interest you for your jewelry :

  • The noble opals : of variable colors, they present the play of lights so sought after opals, they are also the most expensive. The majority of them come from Australia.
  • Fire opals : translucent, their color varies from pale yellow to bright orange and come mostly from Mexico, they are also more affordable than noble opals. There are also opals of noble fire, which are more expensive.
  • The common opals : of variable color, they are opaque and do not show any play of light, in so doing they are economic to mount on a jewel or to constitute an adornment for a more affordable price.

Different types of opal

  • Composite opals doublet or triplet : these stones are not natural but made from natural opal pieces too small to be mounted as is on a jewel. These assemblies make it possible to obtain large opals with natural play of light for a much lower price than natural opals of the same size. They are generally more expensive nevertheless than the common opals.

Opal composition

The composite opals are made partly of natural opal on which is glued a black mineral support (onyx, tinted glass or other). The triplet opal is covered with a layer of quartz to protect it, the quartz is much more resistant to dust abrasion and blows than naked opal.

  • Imitations of opals : it's an artificial stone containing sequins imitating the luminous reflections of a real opal. It is easily recognizable because it doesn't have the diffuse colors of a noble opal.
    synthetic opal Synthetic opal

     

    Here are the different shapes that opals can take on jewelry :

    • Cabochon : oval or free depending on the stone, the cabochon has a flat face to sit the stone on the mount and a rounded part, the most luminous or colored face of the stone. In the case of this photo, it is opal pink opal of oval form and a Boulder opal of free form.
    Pink opal Opal chocolate
    • Raw opal : The opal is released from its rock matrix, but retains the shape given by the rocky cavity in which it formed. Some noble opals too small to be cut can be mounted as set on a ring or as a pendant. The stone of the following photo is a translucent noble opal of raw form too small and irregular to be cut in one of the classic forms of jewelry : round, oval or pear. The play of lights of the opal is obvious while the photographs tend to show only a fraction of the reflections given by the stones.
    Raw opal Raw opal Raw opal
    • Cut opal : it's generally the fire opals that can have light effects that are cut in the shape of oval, round, or pear. They can be cut with facets or not as seen with the two opals below. The one on the left will fit perfectly to be mounted on a ring while the one on the right will be suitable for a pendant or earrings.
    Noble opal trilion fre opal
    • Cantera opal : the opal is still trapped in its rock matrix where it was formed. We can clearly see in this picture the light effects of this noble opal imprisoned in the rock. This one will be perfect to be mounted as a pendant.
    Noble opal noble opal Cantera

    Frame type on jewel opals

    In spite of the great variety of opal, only two or three types of crimps are mainly used to mount the stones on the jewels.

    Opaque opals will accept all types of frames, whether claw, crimped closed or mass crimped.

    The light can not cross these stones, it is the light incident on the exposed face of the stone which once diffracted will give the play of light of the noble opal.

    In the following photo, a noble white opal carved in cabochon is mounted in closed setting on a gold pendant (photo credit).

    The photo on the right shows a white opal ring leaving the stone well exposed to light. We can notice that the photo does not allow to see the effects of diffraction of the stone which are tenuous for this opal.

    Noble opal pendant silver opal ring

    For translucent opals, it's preferable to let light penetrate them.

    Therefore avoid closed crimps to favor a set claws.

    In the example of the ring with opal pictured, only two claws hold the opal in place on a ring allowing the light to penetrate the stone in all directions.

    This is a semi-translucent noble opal with yellow, orange and green hues.

    Silver opal ring worn

    Commonly used also, the crimp mass makes it possible to make touch the stone with the height of the metal surrounding it. In the picture of this ring, the entire frame is covered with opal fragments set with a mass.

    Big opal ring

    Opals maintenance

    The shocks

    Opals are particularly fragile stones and are easily scratched.

    Their hardness is 6 (on the Mohs scale) whereas most of the dust has a hardness of 7.

    In comparison, the diamond has a hardness of 10, the sapphires and rubies a hardness of 9, the emerald a hardness of 8.

    You understand why precious stones such as rubies, sapphires and diamonds are known for their lifespan, they are the hardest stones.

    This is why wearing opals on hand jewelry (rings and bracelet) must be accompanied by special attention.

    You should avoid manual activities when wearing jewelry with opals, including household chores (kitchen, dishes, DIY, storage).

    The chemicals

    Opals are also sensitive to chemicals such as perfumes and cleaning products.

    Again the handling of cleaning products (dishwashing liquid, strippers) is to be avoided if you wear rings or bracelets with opals.

    As for necklaces, pendants and earrings set with opals, it will be necessary to put them after you have perfumed so as not to sprinkle them with perfume.

    The heat 

    Because they contain water, they are also very sensitive to heat and humidity.

    Do not put them near a fireplace or radiator (or any other heat source) at the risk of dehydrating them, which can lead to fractures of the opal of your jewelry or tarnishing it if it is a translucent opal.

    Similarly if you go on a trip, check the climate of your destination.

    A sudden change to a dry climate could affect the appearance of your opal jewelry.

    Cleaning

    To clean your jewelry with opals, avoid any utensil potentially scratch the stone or chemical that may alter it.

    The best thing is to use a soft, damp cloth to rub the stone.

    If your opal is scratched, you can entrust it to a lapidary to polish it again. Attention, it is important to entrust to a lapidary experiment with opals, since the polishing of its stones is delicate, it requires a particular know-how.

    Choose your opal to create your jewel

    For all reasons mentioned above, opals are not recommended when it comes to buying or creating an engagement or wedding ring that will be worn every day (for this type of jewel we will favor hard precious stones such as diamond, ruby, sapphire and emerald).

    If you want to choose a noble opal online, you will need several pictures of each stone from different angles to apprehend all the play of light of the stone.

    It is very common for photos to soften the actual colors of the stone. In the following photo, we can see a noble opal cantera mounted on a ring, the play of light changes according to the orientation of the light and the angle of the shot.

    These photos give a good idea of the quality of the stone.

    noble opal ring noble opal ring noble opal ring

    In the following photos, we can see a ring with a pear-shaped welo cabochon opal.

    Welo opals come from Ethiopia and are the most sought after by the quality and intensity of the colors of the stone.

    Welo noble opals

    Silver ring with welo opal from our jewelry workshop

    If you are looking for a beautiful stone cheaply, it will be good to turn to composite opals (opal doublets and triplets) more affordable than natural opals, but whose colors and lights are natural.

    Finally, if you buy your opal on a production site during a trip, do not buy opals hydrophanes.

    The latter are identical to noble opals when they are immersed in water but tarnish when dehydrated in the open air.

    If you are offered rough stones in a bottle filled with water, beware.

     

    For further :

    October 03, 2019 — Hugo Maherault

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