Cleavage is good. Lath and prismatic shapes are common yielding parallel or inclined extinction. Perthite is the intergrowth of K and Na feldspars, commonly albite in microcline or orthoclase. Perthite may give the appearance of twinning, but the intergrowths often are irregular and not as sharp as twins. Since this is an intergrowth of two feldspars, differential weathering may result in one phase being altered.
Carbonates are commone to many soils, but are easily weathered.
Dolomite may occur pedogenically under certain conditions, but is still considered as a lithogenci mineral. It usually occurs as rhombohedral crystals, but this is not always diagnostic. Recent shell fragments may be recognized by their unique microsturcture and limestone fragments may have included fossils. Distinguishing between pedogenic and lithogenic calcite is not always easy. Staining techniques are often necessary to distinguish calcite and dolomite.