| As the pH of water glass is lowered, colloidal particles of amorphous silica are formed. |
| For most large deposits of agate or silicified wood, silica was derived from the decomposition of volcanic rocks. |
| Consisting of a silica core covered by a metallic shell, the nanoshells capture and focus the passing light, enhancing the Raman effect. |
| An aerogel is a porous network of silica strands with diameters of a few nanometres. |
| The hexane extract was evaporated, redissolved in chloroform and passed through a short silica gel column. |
| A recess is formed in the silica layer that is aligned with an active area within the semiconductor substrate. |
