Your homeowners policy has VERY LIMITED built in coverage - for example, if the ring is stolen, usually the homeowners policy limit is $1,000. And if it goes missing, falls down the drain, or a stone falls loose of the setting in the back yard somewhere, it isn't covered AT ALL.
If you want broader coverage on your homeowners policy, depending on where you live, of course, you can "schedule" it or add a "jewelry" floater to your homeowners policy, at a rate of about $.30 - $1 per hundred dollars of appraised value.
If you want a stand alone policy for it, it will be the same rate, with a "minimum premium" of about $150. That means, if the ring is worth $200, the rate is $.60, but the policy will still cost $150.
Keep in mind, that appraisal you get from the jeweler you bought it from, is usually NOT the price you paid for it. They make you think you got a bargain, by giving you a discount - usually 25%. So you pay $5,000 for a ring, they write up the appraisal for $7,000. The insurance company charges you for the $7,000 price, BUT, if you lose it, they don't cut you a check for $7,000 UNLESS YOU BUY THE AGREED VALUE ENDORSEMENT, which, of course, costs more. What they do, is have agreements with wholesalers, and they'll pay the wholesaler $4500 or so, and the wholesaler will replace the ring, or they'll write you a check for the $4500.
So talk to your agent about valuation, and don't be tempted to use that inflated appraisal unless you want the agreed value endorsement.
Agent, 20+ years