| 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 |