Firstly check the Policy Booklet used by your Insurer to see what the policy covers in relation to valuables. If you use a broker (and you should) he/she will advise as how best to Insure valuable items apart from the normal contents you possess.
When dealing with valuable items such as Jewellery be sure to Insure these separately on the policy or you may not get there full value as Insurers will have limits per item not specifically insured.
My advice is supply your Insurer with a list of these items with current values, photographs and description of each. It may sound cumbersome but will be of huge assistance to you in maximizing your claim settlement if you are unfortunately in the position that you have to make a claim. Paying for a valuation now (pre loss) means no significant reduction in replacement costs later.
Many Insurers also require that with diamond rings that the stones are checked and certified every few years not to be loose. Make sure the paper work is up to date.
You will pay an additional premium for these valuable items but be assured you will be very glad you spent the money in the event of you making a claim.
It can be really upsetting for policy holders when they have to make a claim for their valuables under the contents section of the policy and discover that due to limits on the policy and conditions in relation to proof of ownership and value that they end up having to settle for well below the replacement cost of the items.
Once again a Loss Assessor will assist you with the claim process but having the boxes ticked in advance means no unpleasant surprises later.