The inscription is in white, so it is called white seal.
Stamps are used as stationery printed on documents to indicate identity or signature. Generally, seals should be dyed with pigments before printing. Those that are not stained with pigment and will appear concave and convex after being printed on a flat surface are called steel seals, and some are printed on wax or wax, or wax prints on envelopes. Made of jade, metal, wood, stone, etc. Chinese seal is one of the representatives of Han traditional culture.