Vermiculite Definition


Vermiculite is a hydrated magnesium aluminum silicate mineral which resembles mica in appearance. Vermiculite is formed by weathering or hydrothermal alteration of biotite or phlogopite. Vermiculite is mined using open cast mining techniques where the ore is screened and classified into five different particle sizes namely: Large, Medium, Fine, Superfine and Micron. Vermiculite undergoes significant expansion when heated. The mineral is expanding into worm-like strands. When expanded it drastically increases its volume and absorption ability. It is a silica mineral and are used in agriculture, horticulture, construction and industrial sectors. Vermiculite is also an excellent material for fire-proofing and insulation. It is also used for insulation or as a moisture-retentive medium for growing plants.

Properties of vermiculite

Vermiculite Properties


  • High water retention capacity optimizing water efficiency
  • It enhances germination, root, and shoot development. Vermiculite continues to provide the benefits of moisture retention throughout the growth cycle.

  • High cation exchange capacity (CEC)
  • CEC indicates the value of a soil to retain cation nutrients. The cation process captures available nutrients, ammonia (nitrogen ions), magnesium, potassium and calcium for slow release.

  • Aeration and thermal properties
  • Roots must have adequate level of oxygen from the soil and aeriation is the process that facilitates oxygen exchange.

  • Thermal ‘insulating’ properties
  • Vermiculite has excellent insulation properties

  • Neutral Carrier
  • Vermiculite is a registered animal feed carrier used in pre-mixes in the animal feed industry.

  • Fireproofing