4. Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of revenue

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
Antimony	$	1,507,588	$	1,492,520	$	3,213,411	$	3,174,333
Zeolite		704,172		682,534		1,430,187		1,373,240
Precious metals		60,523		81,293		85,050		141,703
	$	2,272,283	$	2,256,347	$	4,728,648	$	4,689,276

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
United States	$	1,819,707	$	1,878,244	$	3,928,276	$	4,125,935
Canada		139,523		378,103		326,780		563,341
Mexico		313,053		-		473,592		-
	$	2,272,283	$	2,256,347	$	4,728,648	$	4,689,276

Sales of products to significant customers

Sales of products to significant customers were as follows for the three and six month periods ended June 30, 2019 and 2018:

	For the Three Months Ended						For the Six Months Ended
	June 30, 2019			June 30, 2018			June 30, 2019			June 30, 2018
Mexichem Speciality Compounds	$	375,514		$	669,103		$	1,059,525		$	1,397,681
Nyacol Nanotechnologies		267,638			-			404,324			-
Kohler Corporation		454,943			334,778			913,037			651,550
Ampacet Corporation		-			-			-			330,260
ZEO, Inc.		-			185,730			-			-
	$	1,098,095		$	1,189,611		$	2,376,886		$	2,379,491
% of Total Revenues		48.33	%		52.70	%		50.27	%		50.70	%

Accounts receivable from largest customers were as follows for June 30, 2019 and December 31, 2018:

Accounts Receivable	June 30, 2019			December 31, 2018
DanaMart	$	-		$	143,890
Axens North America Inc.		25,121			34,912
Earth Innovations Inc.		-			35,967
Kohler		123,106			-
Nutreco Canada Inc.		27,963			-
	$	176,190		$	214,769
% of Total Receivables		42.25	%		49.00	%