4. Revenue Recognition (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 2,272,283	$ 2,256,347	$ 4,728,648	$ 4,689,276
Antimony
Revenues	1,507,588	1,492,520	3,213,411	3,174,333
Zeolite
Revenues	704,172	682,534	1,430,187	1,373,240
Precious Metals
Revenues	60,523	81,293	85,050	141,703
United States
Revenues	1,819,707	1,878,244	3,928,276	4,125,935
Canada
Revenues	139,523	378,103	326,780	563,341
Mexico
Revenues	$ 313,053	$ 0	$ 473,592	$ 0