The yellow and white color zones in "fried egg" stalagmites, which are deposited from a single water source, are due to crystal texture differences, not chemical or mineralogic factors. The outer zone is porous calcite marked by intergrown crystals and fluid inclusions which reflect and refract the light yielding a white appearance. The inner core is continuous, translucent calcite yielding its true transmitted yellow color. The irregularities in the outer zone are probably caused by incomplete coalescence of the crystallite precursors. The variation may be related to the thickness of the water layer depositing the calcite.