This question was fairly answered by those who attempted it. It is a popular question among the candidates. The question requested the candidates to give the following points:

(a) Definition of Rock
A rock is a naturally occurring solid made up of aggregate of minerals.

(b) Grade and Ore Recovery
As Grade increases Recovery decreases and vice versa

(c) Rock-forming Minerals

• Plagioclase Feldspar
• Potassium feldspar
• Quartz
• Dolomite
• Calcite
• Biotite
• Muscovite
• Pyroxene
• Olivine
• Muscovite
• Hornblende

 (d) Usefulness of Rocks

• Rocks form the main source of mineral deposits such as gold, diamond, copper etc
• They provide essential raw materials for both light and heavy industries e.g. limestone for cement production
• Some beautiful rocks such as marble can be polished as ornaments for decoration in homes, churches and mosques
• Rocks such as coal serve as sources of fuel for domestic and industrial uses
• Rocks serve as tourist attraction e.g. Olumo rock in Abeokuta, the volcanic rocks of Jos.
• Rocks are used in construction works e.g. building of houses, dam etc.