A natural granite that is classified as ¼ inch minus and 3/8 inch plus. Here’s a chart that shows the ¼ inch minus:
Decomposed Granite or 1/4″ minus crushed aggregate screenings
Crushed Stone Sieve Analysis Percentage of Weight Passing a Square Mesh Sieve
1/4″ MINUS AGGREGATE GRADATION
| U.S. Sieve No. | Percent Passing by Weight |
| # 3/8″ | 100 |
| # 4 | 90 – 100 |
| # 8 | 75 – 80 |
| # 16 | 55 – 65 |
| # 30 | 40 – 50 |
| # 50 | 25 – 35 |
| # 100 | 15 – 20 |
| # 200 to | 10 – 15 |
¼ inch minus is even finer than class 2 base and should only be used in very thin layers if the surface is to drain at all.
The final determination on the exact base material is being experimented with at this time.