i am no specialist on vermetids but the "coiling" (or better the way they uncoil) is characteristic at least for some of them. additionally size can be a good hint. also it depends on where you found it. if you provide some more detailed information on locality (i guess it's not fossil?) and images, it would be much easier.
do you have a specimen of vermetid? The genus usually found in India include Dendrapoma spp., Vemetus spp. but it can also confuse you with Tenagodus spp. belonging to family Siliquaridae. So first you must confirm whether the coiled gastropod belongs to vermetidae or siliquairdae. I can help you out with identification since I am in Chennai (NCSCM) and for further details you can contact me at 9941179534. Find below some useful links
http://www.nmr-pics.nl/ - Go into the site and click on the family names on the left side
www.gastropods.com - you can scroll through species pages individually