These jewels are the new blood tile spawn. And blood tiles have always, ALWAYS been considered rare, even when they were spawning.
The blood tile spawn was so scarce to catch, but it did still spawn. Just like these jewels.
There is a grey area that should be tolerated. Heck let a discussion thread be made when an item like this comes out, and let the greater community establish the item as acceptable/non-acceptable.
I often wonder about "big fish". I have fished for over 7 years and never once gotten one above 200 stones. And I have caught thousands of big fish. Now say one day I catch one that is like 220 stones (record so far in UO wide is 225 btw). If I decided to sell, a 220 stone big fish, caught by A Stoned Mariner. Cool name, uber uber rare item. Still potentially spawns, but odds are like 1/100000 or worse, someone going to tell me it isn't a rare?
I dunno...grey area!