Turquoise, wavellite and variscite can be found, however the specimens are very small. Red Beds contain huge deposits of uranium in overseas countries and drilling around Mansfield has located traces of uranium minerals. The small size of the Mansfield Basin and lack of coarser sediments means no economic deposits of uranium occur here. Travelling into the Tolmie Ranges, north of Mansfield, rocktypes change to a sequence of volcanics, consisting of rhyolites and quartz porphyry. Approaching Whitfield, rocktypes again change as we enter the Edi-Cheshunt Slate Belt.
Turquoise occurs as thin veins parallel to the cleavage in the black slates.
Most of the turquoise veins are soft and friable but occasional hard patches do occur. There are many old turquoise diggings in the hills around Cheshunt but often it pays to follow the strike of the black slates until the characteristic blue-green stains are found, marking turquoise veins in the slate. Further into the alpine region around Mansfield lie the Cambrian Greenstones of the Howqua Hills and the gold bearing Mt Easton Slate Belt between Woods Point and Walhalla.