| The Northern Pennine orefield has been an important source of lead, fluorspar, and other metallic and nonmetallic ores for many centuries. |
| When the experiment is performed in the fluorspar tube, the gaseous fluoride may be collected over mercury. |
| In recent years, the number of people who work in informal gold or fluorspar mining has been increased. |
| These sought-after ouzels live among the rusting fragments of mining, the glinting fluorspar and rocky clefts of this once industrious valley. |
| Metallic calcium also burns in fluorine gas, forming the fused fluoride, and occasionally minute crystals of fluorspar. |
| Fluorine never occurs as an element in nature, but is found in minerals such as fluorspar, fluorapatite, and cryolite. |
