Question

Match List - I with List - II 

List - I (Type of Twin)	Associated Mineral
A. Geniculated twins	III. Gypsum
B. Cruciform twins	II. Rutile
C. Butterfly twins	IV. Calcite
D. Arrow head twins	I. Staurolite

 

• A. A-II, B-I, C-IV, D-III
• B. A-II, B-III, C-I, D-IV
• C. A-III, B-IV, C-I, D-II
• D. A-IV, B-III, C-II, D-I

Hint:

Cruciform twinning is typical of staurolite, while arrow-head twinning is common in gypsum.

Answer 1

The Correct Option is A

Concept:
Twinning is the regular intergrowth of two or more crystals of the same mineral according to a definite crystallographic law.

Step 1: Match Geniculated twins.
Geniculated twins are commonly seen in rutile. \[ A\rightarrow II \]

Step 2: Match Cruciform twins.
Cruciform twins are characteristic of staurolite. \[ B\rightarrow I \]

Step 3: Match Butterfly twins.
Butterfly twins are associated with calcite. \[ C\rightarrow IV \]

Step 4: Match Arrow head twins.
Arrow head twins are commonly shown by gypsum. \[ D\rightarrow III \] Therefore, the correct matching is: \[ A-II,\ B-I,\ C-IV,\ D-III \] \[ \therefore \text{Correct Answer is (A)} \]