Question

explain maains types of formation in which minerals occur

Answer 1

Three main types of formations in which mineral occurs are :
(i) Veins and lodes In igneous and metamorphic rocks minerals may occur in the cracks, crevices, faults or joints. Smaller occurrences are called veins and larger ones are called lodes.
(ii) Beds or Layers In sedimentary rocks, minerals occur in bed or layers. They are formed as a result of deposition, accumulation and concentration in horizontal strata, (layers)
(iii) Placer Deposits Certain minerals occur as alluvial deposits in sands of valley floors and the base of hills as placer deposits.

Answer 2

there are 5 types of occurences of minerals:

1.in igneous and metamorphic rocks, minerals may occur in the cracks, crevices,faults or joints. the smaller occurences are called veins and larger are called lodes. eg. tin, copper, zinc, lead etc.

2. in sedimentary rocks, minerals occur in beds and layers. eg. gypsum, potash salt, soduium salt, etc

3. decomposition of surface rocks, and removal of soluble constituents, leaving a residual mass of weathered matherial containing ores. Bauxite is formed in this way.

4.certain minerals occurs as alluvial deposits in sandy and valley floors and base of hills called as placer deposits.
eg. gold,silver,platinum etc.

5. ocean water contains vast quantities of minerals. eg. commom salt, magnesium.