In one instance, platy, highly lustrous white mendipite crystals occur intergrown with the philolithite, as well as native copper and lead.
Philolithite is mineralogically and genetically related to the lead oxychloride "family," which at Langban presently comprises blixite, ekdemite, freedite, heliophyllite, mendipite, nadorite, petite, sahlinite, and sundiusite.
Until the much larger deposits of mendipite were discovered at Merehead quarry, the Higher Pitts mine at Priddy was the main source of specimens of this mineral in the Mendip Hills.
A deposit very similar to that at the Higher Pitts mine is found about 4 km to the north at the Priddy Hill Farm, and this has also produced specimens of mendipite.
Near the surface the rock was seen to contain nests of manganese-ore, and associated with this a little copper-ore had been found, and what was of especial interest the mineral mendipite (oxy-chloride of lead) had also been obtained.
It also formed thin alteration layers on hydrocerussite around nodules of mendipite, epitaxial growths on hydrocerussite crystals, and complete pseudomorphs of hydrocerussite crystals.
The largest crystals known measure about 1 x 3 cm and 1 mm thick; these occur in the largest specimen of mendipite from the Higher Pitts mine (BM 1923, 212; see below).
Crednerite has usually been found as fan-like groups and hemispherical masses of thin, bright black plates on nodules of cerussite, hydrocerussite and mendipite in Mn ore.
It also formed thin alteration layers around nodules of mendipite.
The surface of the mendipite is generally partly altered into hydrocerussite and cerussite, and thin layers of these minerals enclose the nodules.
Pennant's catalog also lists jasper from the Harz Mountains, iron minerals from the Forest of Dean, a fine example of mendipite
from the Mendip Hills, malachite from Ecton, a limonite pseudomorph after chalcopyrite, and many other interesting items.