Standard Specification for Electrodeposited Gold for Engineering Uses	ASTM B-488
ASTM Type	Purity
Type I	99.7% Gold minimum
Type I I	99.0% Gold minimum
Type I I I	99.9% Gold minimum
ASTM Code	Hardness
A	Knoop hardness 90 max.
B	Knoop hardness 91-129
C	Knoop hardness 130-200
D	Knoop hardness 201+
Class	Minimum thickness, um
0.25	0.25
0.50	0.50
0.75	0.75
1.00	1.00
1.25	1.25
2.50	2.50
5.00	5.00