Jasper is a fascinating material with a wide range of possible colors, even in a single specimen. On this example, the carver makes use of the green layer to depict the popular motif of a katydid and cage. For a porcelain example with this subject and a discussion of its symbolism see lot 322.
For a jasper bottle from the Hunter Collection showing a katydid with a cage, see B. Stevens, The Collector’s Book of Snuff Bottles, New York, 1976, p. 135, no. 482.