Dating from the 1800s or possibly the 1700s, a hardstone, possibly agate, has been finely hand carved so that the walls of the upturned leaf are thin and quite translucent. The color of the stone varies from almost clear to a very dark green and it has rust colored inclusions.It appears to be jade but testing with a steel blade indicates that it is not as hard as jade, but it is much harder than soapstone. My best guess is an agate.
The shape is that of a water lily or lotus pad that has been hollowed out to form a bowl. The underside is incised and has tendrils or stems with about-to-open water lilies. The translucence of the stone and quality of the carving, as well as the history of the piece, indicate that it is an antique washer.
Dimensions are 4 3/4" (12 cm) long by 3 1/2" (8.9 cm) wide by 1 5/8" (4.2 cm) deep. It weighs 7.6 ounces (213 grams).The condition is quite good.