Thank you for submitting your item for appraisal. This appears to be a modern bowenite carving in the shape of chinese headrest / pillow, sometimes called "opium pillow" ( which it is not ). Bowenite / Serpentine is much easier to carve than jadeite. The pillow in your possesion shows a pair of bats "fu" ( homonym to fu = luck) and the character "shou" for long life on the lid. The lower part of the pillow / box is decorated with dragons chasing a pearl. The estimate is based on similar items offered or sold at auction. There is no measurement for the sentimental value you might attach to it.