Silica is highly porous and has a number of distinct crystalline forms (polymorphs) in addition to amorphous forms. It is used as a suspending and thickening agent in pharmaceuticals. It is also used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.

• Insoluble in water
• Boiling point: 2230 °C
• Melting point: 1710 °C
• Surface area: 500 to 600 m²/g