Question

How do acidic igneous rocks differ from basic igneous rocks?

Answer 1

Igneous rocks may be classified as acidic or basic depending on their chemical composition.

• Acidic igneous rocks contain more than 65% silica and a low percentage of oxides. They are light in colour and less dense.
  Example: Granite.
• Basic igneous rocks contain a low percentage of silica and a high percentage of oxides (such as iron and magnesium). They are dark in colour and dense.
  Example: Basalt.