Quartz with iron and manganese oxides, Diamond Hill Mine, Antreville, South Carolina. This piece looks a bit like a porcupine! Prismatic quartz crystals radiate out from the matrix, this is similar to spirit quartz. Many crystals are covered by hematite, or have hematite inclusions.
Miniature specimen: about 2.4" x 1.6" x 1.2" (60mm x 40mm x 30mm)