The entire headland forms the Pentire Peninsula Site of Special Scientific Interest, designated for its geology and flora and fauna including nationally rare plants. Important examples noted include slates from the Upper Devonian period, several invertebrate species, predatory birds and grey seals. Pentire Head is formed of pillow lavas, a type of rock found nowhere else in Cornwall, while The Rumps consists of durable Greenstone, and naturally occurring Prehnite has also been found on the cliffs. Other valuable minerals can be found and two mines have operated on the headland over the years. Pentire mine was the first in the locatity having started around 1580 mining for lead ore, four shafts of at least and an adit being driven into the lode. In the mid 19th century another mine referred to as Pentireglaze mine worked an extension of the lode, and also drove 2 shafts into a nearby lode bearing both lead and silver ores, this extending the workings out beyond the headland under the sea, where miners reported hearing ships passing overhead. To achieve this an engine house was erected on the cliff top but production by the grandly named "Pentire Glaze and Pentire United Silver-Lead Mines" ceased in 1857 after several years with no output. Sources are not always consistent between the names of the two mines, but from the mid 19th Century the headland produced over 1000 tons of Lead Ore and of silver. After production ceased the engine house gradually became a ruin and was finally demolished in 1957, this location now being a National Trust car park known as the Lead Mines car park.