158 THE PROSPECTOR'S HANDBOOK. 



DOLOMITE A mineral composed of the carbonates of lime and mag- 

 nesia. Magnesian limestone. 



DRIFT A loose alluvial deposit. A level in a mine. 



DRIVINGS Horizontal tunnels in a mine. 



DRUSE A hollow space in veins lined with crystals. 



DRYBONE A term used in America for calamine (carbonate of zinc). 



DUCTILE That can be drawn out into wire or threads. 



DUMP The place where ore taken from a mine is deposited. 



DUNES Small hills formed by sand blown together by the wind. 



DYKE Intruded igneous rock which fill up fissures and rents in strati, 

 fied rocks. 



E. 



EARTHY COAL Name sometimes applied to lignite or brown coal. 

 EFFLORESCENCE An incrustation of powder or threads, due to the 



loss of the water of crystallization.. 

 ELBOW A sharp bend in a lode. 

 ELECTROLYSIS Separating chemical compounds into their component 



parts by means of electricity. 

 ELVANS Certain granitic and porphyritic rocks that traverse the granite 



and slate rocks of Cornwall. 

 EMERY Compact form of corundum. Is hard enough to scratch quartz 



and several gems. 

 EROSION The wearing away of. 

 EVAPORATE To cause to become a vapour. 

 EXEMPTED CLAIM (Australia) A mine allowed to remain unworked 



some time. 



F. 



FACE The extreme end of tunnel or other mining excavation. 

 FALSE BOTTOM In alluvial mining the term is applied to a stratum 



on which pay dirt lies, but underneath which are other bottoms. 

 FANEGADO (Spain) 9oJF. = 100 acres. 

 FAST Term applied in Cornwall to solid rock immediately beneath the 



surface drift. 

 FATHOM 6 feet. 



FAULT Dislocation along a fissure. 

 FEATHER ORE A sulphide of lead and antimony. 

 FEEDER A small vein running into a main lode. 

 FERRUGINOUS Iron-containing. 

 FILTER To remove the particles of matter in a liquid by pouring it 



on to some substance, such as filter paper, so that the liquid runs 



through and leaves a solid residue behind. 

 FISSURE A crack or rent in rocks. 

 FLATS In mining language, decomposed parts of limestone strata 



which are mineralized. These flats sometimes extend for a long 



distance horizontally, though they are not very thick. 

 FLEXIBLE Capable of being bent without elasticity. 

 FIJNT A massive impure variety of silica. 



