Similar to lamellar but with smaller crystals. Nodular A stone of concentric growth around a center usually composed of mostly one mineral. If broken, may show concentric rings. Forms rounded spherical to oddly shaped concretions. Oolitic Rounded pebble to sand sized nodules in a compact mass formed in sedimentary environs.
Nodules are larger than oolitic forms.
Radiating Distinct crystals arranged in an orientation outward from a common point. Rosetta Petal-like crystals arranged in a flattened radial habit around a central point. Stalactitic A concretionary growth around a usually hollow tube, producing long, slowly, tappering, and rounded masses. Usually formed in caves or other voids in rocks from the precipitation of a mineral from an evaporating fluid. The cavity is sometimes filled with different minerals than the host rock, however.