Everybody must get stoned

on what to look out for while buying jewellery, and the availability of cheaper substitutes.

The biggest trend in jewellery today is mix-and-match "" with women buying stones, even precious ones set in gold, wearing a piece for a single occasion, at best a season, teaming it with a particular outfit and never repeating the pair again. Jewellery, clearly, no longer occupies the Indian mindspace as an investment.

So even as huge gold sets are bought on occasions such as weddings and promptly confined to bank lockers, glamorous stone-studded pieces are really the hottest new buys. But what should you look for while buying stones? More importantly, what are the cheaper substitutes, natural and industrial, for that flawless mega-carat rock that you always coveted?

Indian gemology has conventionally recognised 84 jewels. Today, of course, there are many more thanks to new and continuous discoveries and innovations, and jewellers put the number in the market at 200-300 types of stones.

Of these, diamonds, rubies, sapphires and emeralds (even though they belong to the same family as aquamarines, they are rarer and thus more expensive) are regarded precious stones. Lately, good quality and clear tourmalines, cat's eyes, aquamarines and tanzanites that are fashionable have also become expensive and thus deemed "almost precious".

But the thing to know about all these stones is that often what you may be buying may not be au naturale but heat-treated to enhance colour. Rubies and sapphires (both are corundums, next in hardness only to diamonds) are treated as such and the practice is acceptable and doesn't detract from the value of the gem unless it is top quality, though your jeweller should tell you about it.

Apart from this, there are newer treatments too "" glass is filled into a natural ruby, for instance, in places where there may be a gap and the colour not so good. These practices are acceptable too but check with your jeweller since a "natural" stone will always be more valuable.

Moissanites are the new stones in the Indian market this year. While much cheaper and easily distinguishable substitutes for diamonds have always been around, moissanite, a simulant introduced to the world in 1998, can fool jewellers and buyers alike.

This synthetic silicon carbide crystal is manufactured exclusively in LA by Charles and Colvard. Its natural counterpart has been found only in meteorites and is deep green, but synthetic moissanite is nearly colourless and has a high refractive index and hardness like a diamond's. Moissanite jewellery is now available (Rs 3,500 onwards, "at one-tenth the price of a diamond") at Sparkling Hues, a boutique in New Delhi, that is pitching it as "affordable luxury".

You could substitute rubies, blue sapphires and emeralds too with other stones, suggests Jaipur-based Rajeev Arora of Amrapali jewellers. The perfect ruby "" the best ones come from Burma, Thailand and recently Vietnam; Madagascar and Indian ones are inferior "" should, of course, be "pigeon-blood" coloured. Look also for a silk sheen "" it shouldn't be there in a clear stone.

But while quality rubies can range from Rs 1,000-50,000 per carat, an exact double is a red spinel (Rs 50 per carat). A pink tourmaline that is called "ruby lite" is a substitute for paler hues. In fact, my research suggests that some crown jewels of England and Iran, long thought to be rubies, are actually spinels.

Now, spinels can also be synthetically produced, but that's quite another matter. But one thumb rule while buying a ruby is: better pink than dark (brownish) if it is not a perfect red of a traffic light.

A dark green emerald can come for anywhere between Rs 2,000-3,000 to Rs 50,000-60,000. The best ones come from Brazil, Colombia and some from Pakistan. It is very difficult to get a clear emerald because there will always be flaws.

If yours doesn't have any, chances are that it has been heat-treated or filled with coloured oil or treated with a new laser technique, which are all acceptable. But much cheaper alternatives could be green onyx (Rs 40-200 per carat "" Arora says most "onyx" in the Indian market is agate anyway) or fluoride.

Almost 90 per cent of the sapphires (the best come from Sri Lanka or Burma) are heat-treated to enhance their colouring. Often, a gemological inspection of your blue gem will reveal that it is coloured only from the top and bottom and is white in between (this is done through a technique called diffusion).

So, says Arora, "if your stone looks too perfect and not expensive", get it tested. On the other hand, you can opt for cheaper tanzanites, kynites and iolites that are good substitutes for blue sapphires that cost Rs 50,000-1 lakh per carat.

Another advantage of a tanzanite is that larger stones are less likely to have flaws (at least to the naked eye). And if you are stuck on the colour blue, you should also perhaps know that all blue topaz is actually white and colour treated in Thailand before being cut and polished.

Precious stones apart, turquoise is one of the trendiest buys this season. But there is hardly any natural stone available here. Much of what you buy is reconstituted"" dust is stabilised and assembled into bricks from where individual stones are cut.

Cheaper artificial turquoise is available too but you can see the differences; the surface is smooth, veins regular. Yet, this comes just for Rs 4-5 per carat as opposed to Rs 50-300 per carat for the natural stone. So the next time you buy, look carefully.