Srimad Bhagavatam Canto 10, Chapter 56, Text 11

SB 10.56.11

dine dine svarna-bharan
 astau sa srjati prabho
 sarpadhi-vyadhayo ’subhah
na santi mayinas tatra
 yatraste ’bhyarcito manih
Each day the gem would produce eight bharas of gold, my dear Prabhu, and the place in which it was kept and properly worshiped would be free of calamities such as famine or untimely death, and also of evils like snake bites, mental and physical disorders and the presence of deceitful persons.
Srila Sridhara Svami gives the following sastric reference concerning the bhara:
caturbhir vrihibhir guñjam
 guñjah pañca panam panan
astau dharanam astau ca
 karsam tams caturah palam
tulam pala-satam prahur
 bharah syad vimsatis tulah
“Four rice grains are called one guñja; five guñjas, one pana; eight panas, one karsa; four karsas, one pala; and one hundred palas, one tula. Twenty tulas make up one bhara.” Since there are about 3,700 grains of rice in an ounce, the Syamantaka jewel was producing approximately 170 pounds of gold every day.
Srimad Bhagavatam Canto 10, Chapter 56, Text 10
Srimad Bhagavatam Canto 10, Chapter 56, Text 12