# d50

The table below lists the D50 values of different sediment classes:

| Sediment class | Size \[µm] | Approximate size             |
| -------------- | ---------- | ---------------------------- |
| Boulders       | > 256,000  | > Volley ball                |
| Cobbles        | > 64,000   | > Tennis ball                |
| Pebbles        | > 2,000    | > Match Head                 |
| Coarse Sand    | 1,500      |                              |
| Medium Sand    | 375        |                              |
| Fine Sand      | 94         |                              |
| Coarse Silt    | 47         |                              |
| Medium Silt    | 11.7       | Not visible to the human eye |
| Fine Silt      | 4.9        |                              |
| Clay           | 1.95       |                              |