Zodiac opium weights were often adjusted to match the modified mass unit which varied over time by removing a little alloy from the base of the weight. Laotian and Siamese opium weights were generally less accurate than Burmese weights. The mass scales varied from 11.8 grams to 16.3 grams. In 1826AD the mass unit was reported as 11.8 grams.
By the 1800s a variety of animal weights were in use and even traded as currency and include birds, snakes, buffalo, rabbits, dogs, horses and monkeys.
* Earth to Heaven: The Royal Animal-Shaped Weights of the Burmese Empire Paperback , 2002 by Joan & Donald Gear
Height: 4.4cm, 1.7in
Base: 2.5cm, 1 in
Weight: 73 grams
Period: Early 19th Century