Blue in colour, tanzanite was discovered about a decade ago. However, due to non-availability of a heating technology then, it could not occupy the due place in the world market. Things changed for the good about six years ago as the heating technology was developed and since then it has been a smooth run for the coloured stone.

Gem traders in the pink city, known for the emerald cutting and polishing the world over, call the tanzanite as a `rising star'. But they fear that like Alexzenderite, which was also a craze in the world market some years ago, tanzanite will also disappear `once the fashion is out'.

Only the traditionally known coloured stones such as emerald, ruby and sapphire are going to stay in the world market, says Ramshmi Durlabhji, a major emerald trader. Durlabhji is firmin his views that the future of these stones is indeed bright and the present setback is temporary.

The share of emerald in total coloured exports fell to a mere 50 per cent in the last one year from 90 per cent at the end of the 1970s. Apart from the tanzanite, the other known coloured stones are turmaline, garnet, aqua-marine, iolite, lapis, etc.

India's exports of coloured stones fell to $132 million during 1997-98 from $136.94 million in the previous year. The total exports during 1995-96 were to the tune of $147.32 million.

Trade circles say that the non-availability of good quality rough gemstones is the main reason for the lower exports. But there is no denying the fact that the world trade is on the decline with the margins continuing to shrink.During 1996-97 the total imports of rough gemstones were to the tune of Rs 255.03 crore as against Rs 235.94 crore in the earlier year. In other words, the value addition is quite substantial, informs Alok Kala, who edits a well-known journal devoted togems and jewellery.

Kala said that tanzanite continued to grab the world market of coloured gem stones at present. During the last four months its prices went up by at least 30 per cent. Due to its hardness and good shine it had caught the imagination of world buyers.

Kala's views have also been endorsed by Manish Totuka, who is in the trade of cutting and polishing of tanzanite. Due to some problems in some of the mines in Tanzania the availability of roughs had become difficult. ``The problem will be shortlived'' says Totuka. According to Totuka, tsavorite was also a craze some time back but as the proper sizes were not available its business had nosedived. Emerald is found in Columbia mostly but, of late, Israel and Brazil have also become the cutting and polishing centres in addition to Jaipur.

However, the emerald prices crashed by 40 per cent after Japan discovered that the imported precious stone had some basic flaws. It was alleged that the cracks in the stone were filled up by resin in such away that an ordinary glance would not reveal (about the existence of cracks).

After it came to light the International Coloured Gemstone Association, USA, made it mandatory that the treatment of the precious and semi-precious stones had got to be disclosed.

Depending on the quality emerald even sells at Rs 5 lakhs per carrot as against the normal rates ranging from Rs 10 per carrot to Rs 1000 per carrot. `The price standardisation in such precious stones is not possible'', says Kala.

The world trade of coloured stones is put at Rs 5000 crore with India's share being less than 10 per cent (Rs 450 crore). Like Diamond there is no agency available in the country to promote the business of coloured stones. In Bangkok, Columbia, Germany, China etc lot of promotional efforts were being made to boost the sales of coloured stones. In the pink city about 50,000 persons are employed in the business of coloured stones - their monthly earnings vary from Rs 10,000 to Rs 25,000. ``Our labour is cheap with highskills'' says Kala.