Fine arts policy or better known as a personal articles floater is an add on policy, in addition to your homeowners insurance, or as a stand alone policy and is used to insure valuable personal property that often requires more coverage than what is provided by an insured's homeowner policy, due to various exclusions and limitations on homeowners coverage. This type of policy would insure your jewelry, paintings, or collectibles like that valuable baseball card collection, stamp or coin collection, or a collection of dolls or figurines.
You can purchase a policy that covers these items up to its full appraised value and will cover a much broader range of scenarios then what's typically covered under a standard homeowners or renters policy.
On a homeowners or renters policy you are typically limited in coverage on jewelry and collectibles to a minimal dollar limit and a standard policy does not insure you for the value we place on an item. All paintings are just a canvas and paint but a Picasso is much different in value then your grandmothers self portrait - the value isn't in the item itself as they are both a painting, essentially canvas & paint, but drastically different in value. The value lies in the rarity or designer/painter, so although one is sentimental and one is rare and valuable they both boil down to a canvas and ink and at claim time, under a homeowners policy, you'll get just that - the cost to replace canvas of like size and some tubes of paint - not really replacing it is it ? This is why you purchase a personal articles policy. This will ensure that you get the value of that item.
A homeowners policy will cover you for fire or wind damage to your diamond ring but is that likely to happen if its on your finger? What's more likely to happen is while on vacation swimming in that beautiful water you discover the stone is missing or you took your ring off in the bathroom to put on lotion and forgot to put it back on or you just simply misplaced it - this is called mysterious disappearance which is not covered under a homeowners policy but is covered under a personal articles policy.