Signet Ring

A type of jewellry, usually worn upon  bearing a personal crest or seal, used to leave an identifying mark upon a document, usually by pressing the ring into hot wax, or occasionally ink. This identifying mark is often used to seal the document, proving the identity and authenticity of the sender.
While signet rings themselves are relatively common, each individual ring is unique, bearing the personal seal of its owner.
Signet rings are popular among noble houses and other individuals of importance, but are relatively rare among the common folk of the land. This is not to say that they are exclusively the preserve of the wealthy, but a family signet of a commoner is unlikely to be worn as day-to-day jewelry; perhaps only being brought out of safekeeping for extremely important uses.
Typically individuals within a noble house will each have their own personal variation on the family crest engraved as their signet, with the head of the household possessing the most ornate of the family's rings. This ring is typically passed down from each head of the house to the next, as a signifier of their authority within the family, as well as their standing in the wider world. While other rings may be passed down, the personalisation of many individual seals means that they are typically included in the grave goods of their owners, or destroyed outright upon their death.
Most signet rings are made of metals, although certain rare examples have been known to be cut from precious stones and gems.
In a darker turn, within the rarified air of the royal and noble court, the signet ring has been co-opted into the process of hiring the mysterious Velvet Court - an elite guild of assassins who cater purely to the richest members of society. As with much of courtly protocol, different varieties of rings are expected to be worn on particular fingers, and the surreptious wearing of a signet ring upon the wrong finger by an individual is used to signal the guild's unseen operatives of a wish to discuss their employment. While on the surface this may seem to invite accidental overtures from those who are simply ignorant of how they should wear their jewellry, the guild has eyes everywhere, and have become experts over the centuries at sorting the genuine mistakes from those who would seek their deadly services.

Rarity

Common, but Individually Unique.

Weight

3-10g

Raw materials & Components

Metals (Typically)
Precious Stones (Rarely)