Generous size intaglio seal signet ring. Some loss to the rim of the gold housing.

 Excellent weight with the back completely in gold- the carnelian only shows to the cut face. 

 Not marked, tests as 9ct. Difficult to date with such simple styling and no marks , Victorian or Georgian . Both were keen  on philosophers. The housing was made to hold the intaglio so one may be older than the other. 

Head size 0.85 by 0.6 inch

Weight 7.5 gms