"Fire opal" causes more confusion than any other term in opal, because it is used for two different things. Strictly, fire opal means opal with a warm body colour — yellow, orange or red — as distinct from the milky or dark backgrounds of other types. Loosely, people use "fire" to mean the flashes of colour that all precious opal shows. Worth knowing which one a seller means before you compare prices.

The stone

2.10 carats, which is 2.31 ratti. Shape: oval cabochon. Origin: Australia. Rs. 10,500, about Rs. 5,000 per carat, reference GS-000575.

Body colour and play-of-colour are different things

• Body colour is the stone's own colour, seen whichever way you turn it. In fire opal that is the warm yellow-to-red range.
• Play-of-colour is the flashing that moves as you tilt the stone, produced by microscopic silica spheres diffracting light.
• A stone can have either or both. Some fire opal shows no play-of-colour at all and is valued purely for its body colour and transparency; material with both is scarcer.

When you compare two fire opals, work out which quality you are being sold on. A richly coloured stone with no flashes and a pale stone with brilliant flashes can carry similar prices for completely different reasons.

Judging one

Start with the body colour: a saturated, even warm tone beats a patchy or washed-out one, and depth of colour matters more than which exact shade. Then check transparency — fire opal is often more transparent than white opal, and clean material without cloudiness is worth more. Then look for play-of-colour: tilt it slowly through a wide arc in daylight and see whether flashes appear, how bright they are and how much of the face they cover. Ask us on WhatsApp at +92 308 887 3888 for a video under moving light; with opal it tells you far more than a photograph.

Is it stable?

Worth asking of any fire opal. Some material from some fields is prone to crazing — the fine network of surface cracks that opal develops when it dries out. It is not a defect you can see coming, which is why the handling advice below matters more here than with a harder gem, and why we would rather you kept the stone away from heat and dry air from day one.

Solid opal and treatment

We sell solid natural opal, not doublets or triplets — look at any opal edge-on for a straight glue line. Solid opal is usually untreated, though some is smoke- or sugar-treated to darken the background; this stone has not been tested and the specification says so rather than claiming otherwise. Independent laboratory testing can be arranged and a certificate of authenticity comes on request.

Care

Opal is 5.5 to 6.5 on the Mohs scale and holds water in its structure. Soft damp cloth only — never ultrasonic or steam. Keep it out of prolonged direct sun, hot cars and very dry air. A bezel setting protects the edge better than claws.

Ordering

One piece only. Flat Rs. 500 delivery anywhere in Pakistan, insured and tracked, dispatched in one to two working days. Cash on Delivery, seven days to return it unused. Measurements on request. More in the Australian opal collection.

This particular stone

This listing is one natural australian opal with a weight of 2.1 Carat. Its price is Rs. 10,500 — roughly Rs. 5,000 for each carat. Origin: Australia. Treatment: treatment not tested. Quote reference GS-000575 when you message us about it. The photographs show this exact stone, so what arrives at your door is the piece you chose on screen.

Between two and six carats is the range most people choose for a gents' ring or a noticeable pendant. Here colour drives the price more than size does, which is why two stones of near-identical weight can be priced very differently.

Whoever you buy australian opal from, make sure of three things: the stone is natural rather than lab-grown, glass or glass-filled; any treatment is stated in writing; and the weight quoted is the weight of the finished stone. We check every australian opal for those three points before it is listed, a certificate is available on request, and because you pay on delivery you can look at the stone — or have it tested — before any money changes hands.

We sell natural stones only and inspect each one before it is listed. Treatment for this stone: Treatment not tested. Certificate available on request. As general background (not a statement about this stone): Solid opal is usually untreated; some opal is smoke- or sugar-treated, and doublets/triplets exist — we sell solid natural opal. Ask us on WhatsApp and we will tell you what we know about this exact stone; independent lab testing is available on request.

A certificate of authenticity is available on request for this stone, and independent laboratory testing can be arranged. Because you pay on delivery, you can also take the stone to a lab of your choice within the 7-day return window. Read more on our authenticity page.