'Prized' is one of the new negative modifiers, it increases the cost of insuring the item (I don't know by how much)
Resists on jewellery are generally not viewed as a good thing, and I think with this ring having SSI as well, the total amount of useful properties that can be imbued on it will be low - which is a shame because 10SSI by itself would be fantastic, even with the HCI and DI would be very good.
As for how much it's worth, that just depends on who is planning a template that the item fits, the only way you'll know is by asking in places like this
