The LIGHTNING PEAK PERIDOTE showing forms the summit of Lightning Peak.

The showing consists of olivine crystals in lherzolite xenoliths within the plateau basalts of the Miocene-Pliocene Chilcotin Group. A remnant cap of the Chilcotin Group forms the summit of Lightning Peak, overlying metavolcanics and metasediments of the Devonian-Triassic Harper Ranch Group.

The host basalt at Lightning Peak has been dated at 2.5 plus or minus 0.1 Ma by K/Ar analysis (Exploration 1995, page 129). The xenoliths are subrounded and range in size up to 15 centimetres. They are composed of a granular to porphyritic mixture of green olivine (70-85 per cent), dark brown orthopyroxene (5-10 per cent) accompanied by accessory bright green clinopyroxene (chrome diopside), and black spinel/magnetite. Porphyritic olivine crystals (clear peridote) are up to 1 centimetre in size. There is no record of exploration for peridote at this showing.