| S. No. | Sial | Sima |
|---|---|---|
| 1. | This is the uppermost layer of the earth's crust. | This is below the Sial layer. |
| 2. | Its thickness is nearly 20 km. | Its average thickness is about 25 to 30 km. |
| 3. | It is composed of Silica(Si) and Aluminium(Al). | It is composed of Silica(Si) and Magnesium(Mg). |
| 4. | It is not a continuous layer. It is not found on ocean basin. | It is a continuous layer. |
| 5. | It is less dense. | It is more dense. |
| 6. | It is Granite layer. | It is Basaltic layer. |