According to the Gems and Jewellery Export Promotion Council (GJEPC) data, exports stood at $26.1 billion in the same period last year.
The labour-intensive sector contributes about 14 per cent to the country's overall export.
The drop in shipments is mainly due to negative growth in the export of gold jewellery and gold medallions and coins.
The industry has asked for support in terms of increasing incentives under the Merchandise Exports from India Scheme (MEIS) to boost the shipments.
Blockage of working capital due to GST is impacting exports, a GJEPC official, who do not wish to named, said.
As per the data, gold jewellery shipments during April-December 2017-18 dipped by 4 per cent to $7 billion.
Similarly, export of gold medallions and coins contracted by about 55 per cent during the period.
However, silver jewellery exports went up 16.28 per cent to $3.11 billion during the nine-month period of the current fiscal.
India's main export destinations are the US, Europe, Japan and China. America accounts for about one-fourth of the country's total gems and jewellery exports.
During the nine-month period of the current fiscal, consignments worth $5.82 billion were returned compared with $5.83 billion during the same period previous year.
China is the biggest competitor of India in the sector.
On the other hand, import of rough diamonds rose 10.87 per cent to about $14 billion in April-December period.
Import of gold bars too increased by about 13 per cent to $3.87 billion.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)