Zodiac opium weights, including the elephant, 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.
According to Gear*, while elephant weights are found occasionally in Laos, Burma and Yunnan, there is little doubt that the origin of elephant weights was in north-west Siam, the former Lan-Na kingdom of Siam (Thailand) and not Laos, the former Lan Chang. It’s thought that elephant weights made their first appearance in Siam as early as 1581AD. 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. Elephant weights were cast in Phongsali, northern Laos, and Siam.
Genuine elephant weights have a distinctly dark grey/silvery patina. This weight is most likely early 19th century or possibly late18th century.
* Earth to Heaven: The Royal Animal-Shaped Weights of the Burmese Empire Paperback , 2002 by Joan & Donald Gear
Height: 4.1cm, 1.6in
Base: 3.5cm, 1.4 in x 2.8cm, 1.1 in
Weight: 150 grams
Base lines: 4
Sign: 4 ray star
Period: Early 19th C