Question

Consier the following statements:

1. Mica is a clay mineral.
2. Rock dust particles, even of clay size are non-plastic
3. A particle of kaolinite is electrically charged.

Which of these statements are correct?

• A. 1, 2 and 3
• B. Only 1 and 2
• C. Only 2 and 3
• D. Only 1 and 3

Answer 1

The correct option is C Only 2 and 3

(c)
Feldspars are the most common rock minerals which account for the abundance of clays derived from the feldspars on the earth's surface. Quartz comes next in order of frequency. Most sands are composed of quartz.
Mica constitute very small fraction of original igneous rocks and thus it can not be said to be clay mineral.
Rock flour (rock dust particles) generally consists of more or less uniform size grains of quartz and they are least plastic varieties.
Electrical charge on kaolinite is responsible for plastic behaviour of soils and cohesion in clays.