De waardefactoren
Een taxateur weegt bij deze categorie een vast aantal criteria. Hieronder leggen we ze uit, in de volgorde waarin ze doorgaans worden bekeken.
Crest integrity — the central criterion
A gold signet ring was made to be used as a seal: the crest was pressed into warm wax. Decades of use wear down the relief. An appraiser first looks at the sharpness of the contours, the depth of the engraving, and whether later hands have re-engraved the crest. An original, sharp engraving — even if it is less deep due to wear than when new — is considerably more valuable than a technically better but later re-engraved example.
For family crests, historical traceability is the second factor. A crest that can be verified in heraldic registers and linked to a documentable family gives the ring an extra dimension that translates into the auction price.
Blank signet ring — the separate market
A blank signet ring (without a crest) or a lightly engraved ring with only initials is primarily judged on material and design. Advantage: resalable to a new owner who can have a crest engraved themselves. Heavy 18kt work from the mid-century or retro period in blank form regularly fetches between eight hundred and two thousand euros on the trade market.
Stone intaglio — carnelian, bloodstone, agate
Signet rings with an engraved stone (intaglio) are a separate category. Carnelian (red-orange), bloodstone (dark green with red spots), and black agate are the classic choices. The quality of the intaglio engraving itself — depth effect, precision, age — determines most of the value; the surrounding metal is supplementary. Antique intaglios (eighteenth or early nineteenth century) set in a later gold mounting are a classic collecting category.
Weight and fineness
Signet rings are traditionally solid. An 18kt men's signet ring often weighs between 12 and 25 grams; a ladies' version between 5 and 12 grams. The weight × carat factor × daily rate gives the intrinsic lower limit. Caution is advised with light, hollow constructions — a 'signet ring' that is strikingly light is sometimes a modern hollow imitation of a classic design.