Hi! Yes, I would get new appraisals. I actually just did this recently due to skyrocketing prices on some jewelry brands/gemstones.
If you have a jewelry rider for your higher end jewelry, jewelry riders will only pay you insured the item for.
I am not aware of any jewelry rider that will pay you more than the insured amount; otherwise, everyone will want to "under insure" to get chaper rates. A jewelry rider is different than a homeowner's insurance policy which will use fair market value, but even then, there is a total maximum limit on the insured homeowner contents.
As an extreme example of a jewelry rider, if you insured your diamond for $100K, and it is now worth $500K, insurance not going to pay you $500K as that is not the amount you insured it for. If under insuring were possible, everyone would insure their fine jewelry pieces for $10.00 to get the lowest rate and maximum payout.
You mentioned you have Jewelers Mutual, and here is their clause that says they will only pay you up to the insured amount, after your deductible, if you have one:
3. How does the deductible work? Once you are satisfied with your repair or replaced item, if you have a deductible on your policy you will pay that amount to the jeweler and the jeweler bills us for the remaining balance (up to the limit you insured the item for).
Life happens. No matter how hard we try, we cannot plan for the unexpected.That’s why you get home, auto, life, and, of course, jewelry insurance. It’s your safety net so that if something happens, you can fix it and forget it. But how exactly do you file a jewelry insurance claim? What do you...
www.jewelersmutual.com
So yes... it is a good time to reassess your insured jewelry pieces.
You are absolutely correct that some jewelry has doubled. My policy is adjusted annually for inflation, but jewelry price increases have exceeded inflation. I just redid my jewelry rider a few months ago.
What I did was pull my jewelry rider with the currentlyu insured prices . I then compared it to the current prices. For the pieces I have that are readily available at boutiques/online where I saw had a big price difference, I asked the company for an updated appraisal to reflect the current price. I did not do this for pieces where the price difference was small.
Prices on generally available created pieces such as Tiffany/Schlumberger, Cartier, and VCA can be found online so you can compare. However, prices on pieces that are unique such as diamonds and pearls cannot be done this way. This is because each diamond is priced unique, and each pearl strand has its own quality grading. The best you can do is to go online to get a ballpark of the curernt price and then estimate how much your piece would be. If there is a large price diference, then yes, get a new appraisal.
I have a Tiffany dianond engagement ring and several Mikimoto pearl strands, and I sent them directly to the boutique to get an updated appraisal. As FYI, pearl prices have skyrocketed over the past few years, and depending on when you got your engagement ring, large diamonds have also increased in price. Since you mentioned Tiffany, as FYI, my Tiffany diamond ring has tripled in price, so I would definitely investigate your diamond. Some Schlumberger pieces, especially the more exotic pieces, have also gone up a lot in price. Part of this is also due to LVMH's purchase of Tiffany and wanting to relaunch and focus on Schlumberger.
A bit off topic...
Since you like Schlumberer, and if you wear short pendants, Tiffany launched a Bird on a Rock pendant! It's gorgeous! Best short pendant ever!
Back on topic...
Significant price increaes are also true of fine colored gemstones. If you have fine colored gemstone pieces such as rubies, emeralds, Paraiba tourmalines, these prices have spiked.
This "re-appraising" exercise I just finished was actually kind of fun. It felt good that jewelry appreciates (at leastnin the eyes of an insurance company, and not true resale value). This exercise also made me think if I wanted to add other pieces that had appreciated in value to my policy as well as removing some pieces, which I did both. I keep a spreadsheet of my fine jewelry purchases, so if you think you might want to do this also, now is the time since you are digging up all your receipts.
Hope this helps. Good luck and have fun doing this!