Distinguish between veins and lodes as forms in which minerals occur in igneous and metamorphic rocks.

Question

Accepted Answer

## Model Answer **Veins:** When minerals in liquid/molten or gaseous form are forced into cracks and crevices in rocks and solidify, the *smaller* occurrences are called **veins**. **Lodes:** When the same minerals occur in *larger* quantities filling bigger joints or faults in igneous and metamorphic rocks, they are called **lodes**. Major metallic minerals like tin, copper, zinc and lead are obtained from veins and lodes. *Source: Chapter 5, Mode of Occurrence of Minerals* --- ## Explanation - The key distinction examiners expect is **size**: veins = smaller occurrences; lodes = larger occurrences. Many students miss this and write identical descriptions for both — that loses marks. - Mention the **process** (molten/gaseous minerals forced upward, cool and solidify) briefly — it adds value and is from the same paragraph. - Giving an example mineral (tin, copper, etc.) rounds off the answer neatly for 2 marks.

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