Why do opals get cloudy

The opal will expand and crack. Fact : Solid opals cannot be damaged by getting wet. However, doublet and triplet opals non-solid, partially man-made layered stones can be damaged by prolonged exposure to water. Water penetration can eventually cause the glue to deteriorate and the layers to separate, causing the opal to take on a foggy, grey, or cloudy appearance. Fact : If an opal was completely black, it would also be completely worthless.

Black opals display a myriad of rainbow colours, and the more colourful the better. Top quality black opals can be more valuable per carat than diamonds.

Fact : Strong light will only make your opal shine brighter. However, be wary of very hot lights as extreme heat can cause opals to expand and crack. Myth : Rubbing oil or detergent on your opal will damage or discolour it. Fact : Oils, detergents and many other common household items will not damage your opal.

However, we recommend steering clear of harsh chemicals and cleaning products such as bleach, chlorine, oven cleaner and other strong chemicals. Solid opals may eventually need to be re-polished after a number of years due to tiny scratches on the surface removing the fine polished appearance of the stone.

The stone will need to be polished by an experienced opal cutter using professional equipment. Myth : Taking your opal to high altitudes in a plane will cause it to crack. High altitudes will not affect your opal. The only major things that can damage your opal are impact, extreme fluctuations in heat e. Extreme variations in heat cause the opal to expand and contract, causing cracks or crazing.

Fact : Wetting your opal in any kind of water will make it look better. This is only temporary. The only true way to maximise the colour of a stone is to have it professionally polished. Rose water has no special properties for enhancing opals. Opal has also been considered a good luck talisman and lucky charm throughout the ages, and has been prized by many civilisations.

Triplets consist of a thin slice of opal glued to a black backing, which is designed to imitate black opals. The triplets have a third layer of crystal, glass, or quartz capping to round off the stone and give it a cabochon. Read more about doublets and triplets. This type of opal can show excellent play-of-color.

Water opal might or might not display play-of-color. If it does show play-of-color, it is faint and covers only small portions of the gem. No matter the color or combination of colors, play-of-color must be vivid to command a high rating. In other words, opal lovers prize bright play-of-color over faint play-of-color.

Not every precious opal, however, sparkles with every color of the rainbow. In some, the play-of-color consists of just one main color and two or more secondary colors.

Desirable play-of-color is further broken down by the colors themselves. Traditionally, red is considered the best prominent color, orange the next most desirable, followed by green.

However, favored colors can vary with fashion or personal preference. Like the shapes you see in the clouds, play-of-color takes many forms. In general, connoisseurs prefer large, closely arranged patches of color over tiny, scattered dots. As with any play-of-color, no matter what the pattern, colors must be bright for the stone to be valuable. A dead spot is an area of the gem in which no play-of-color appears and only background color is visible.

Dead spots detract from opal value, especially if there are several of them. With an opal, clarity is its degree of transparency and freedom from inclusions. Experts prize different levels of clarity for different opal types. For example, in crystal opal, experts admire transparency, while in black opal they prefer an opaque background. Each provides the best background for displaying play-of-color in its individual opal type.

A cloudy or milky background color lowers the value of any opal. It makes the gem less attractive, and it can sometimes signal a lack of stability. There are various types of opal clarity characteristics that affect value. Opals, like other gems, can have fractures, or pits and other surface blemishes. An opal might also contain fragments of its host rock, called matrix.

Matrix in a polished opal is usually—but not always—detrimental to its appearance and value. It depends on the type of opal. The moisture loss can be caused by heat or excessive dryness, or by exposure to bright light or direct sunlight. For quality control, producers and dealers single out opals that they suspect might ultimately craze.

Dealers who willingly buy crazed opal do so because it commands a lower wholesale price than undamaged opal. This means they can sell it at a lower retail price level. As with many top-quality colored stones, exceptional opals might not be cut to standard sizes and shapes. Cutters usually fashion exceptional rubies or sapphires, for example, in a way that saves weight or maximizes color— even if the result is an unevenly proportioned gem.

In a similar strategy, opal cutters usually cut top-quality rough to show off its spectacular play-of-color. To achieve this goal, cutters might fashion fine opals into large, irregular shapes that keep as much play-of-color as possible. Designers set these costly one-of-a-kind gems into custom pieces. On the other hand, cutters typically fashion commercial-quality white opal and assembled opal into standard calibrated sizes, usually ovals.

The cut of a fine opal should be symmetrical. Domed surfaces give the best play-of-color, and make the stone appear vivid from most viewing angles.

If the cabochon is flat, it might be vulnerable to breakage, especially during setting into jewelry. Opals come in a wide range of sizes and carat weights.