The park was a granite quarry for extracting a form of norite called Gombak norite. Rapakivi granites are often found associated with intrusions of anorthosite, norite, charnockite and mangerite. One is a mafic unit with gabbro, norite, amphibolite and anorthosite. Another occurrence is as cumulate in gabbro and norite layered intrusions. In geological terms, black granite might be gabbro, diabase, basalt, diorite, norite, or anorthosite. Magnesian orthopyroxene occurs in plutonic rocks such as gabbro (norite) and diorite. These mines are also one of the few places where "Spheroidal Norite" is found. Often, cumulate layers are polyminerallic, forming gabbro, norite and other rock types. The belt has norite and enderbite intrusions of calc-alkaline chemistry. "Shiro No Norite" ("The White Rider") is a Tokyo-based group of fans, established in 1981. Sudbury gabbro varies between a gabbro and a norite, depending upon the local silicates' ratios. The name "norite" is derived from "Norge", the Norwegian name for Norway. It is a norite with extensive chromitite and sulfide layers or zones containing the ore. Gabbro and norite often occur in the upper portions of the layered ultramafic sequences. Norite is a common rock type of the Apollo samples.