Consider the following statements with reference to Feldspar mineral : 1. Half of the earth's crust is composed of feldspar 2. It has light cream to salmon pink colour 3. Magnesium is a common element in all types of feldspar Which of the statements given above is/are correct ?

Feldspar is the most abundant mineral group in the Earth's crust, with sources stating it composes approximately half [1] or even up to 60 percent of the crust. Statement 1 is therefore correct. Physically, feldspars are characterized by light colors, typically ranging from light cream to salmon pink [1]. Statement 2 is correct as these are the standard diagnostic colors for common varieties like orthoclase. Regarding chemical composition, feldspars are aluminosilicates containing varying proportions of potassium, sodium, and calcium [3]. While magnesium is a common element in the Earth's crust and is found in minerals like olivine and pyroxene [3], it is not a constituent element of the feldspar mineral group [1]. Instead, the primary cations in feldspar are K, Na, and Ca [1]. Thus, statement 3 is incorrect.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.5. Some Rock-Forming Minerals > p. 175
2. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > The Crust > p. 53
3. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.5. Some Rock-Forming Minerals > p. 176