|Figure 2-4. Large botryoid of aragonite (A) from a stalagmite from Madagascar. Dark area in botryoid (red double-pointed arrow) is due to extinction of vertical crystals in cross-polarized light. Termination of crystals in right side of A against smaller cluster at right (a) suggests that the smaller cluster grew first and blocked growth of A in that direction. Black areas (V) are void space; truncation of aragonite crystals (e.g., white arrow) suggests that some or much of that void space is the result of dissolution of aragonite.
Photomicrograph was taken in cross-polarized light; field of view is 2.1 mm wide. Anjohibe Cave, Madagascar; Sample MA2; thin section MA2-6. Sample collected by Dr. George A. Brook.
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