_Calcium fluoride_, CaF_2, constitutes the mineral fluor-spar (_q. v._), and is prepared artificially as an insoluble white powder by precipitating a solution of calcium chloride with a soluble fluoride. ❋ Various (N/A)
The centers of the fluor-spar cubes become negatively electric by the action of light. ❋ Various (N/A)
Hantzel has communicated to the Saxon Royal Society of Science some interesting observations on the production of electricity by light in colored fluor-spar. ❋ Various (N/A)
Of this fluor-spar were formed the celebrated murrhine cups which were in use in Rome in the days of Pliny among the richest people, and for which fabulous prices were paid. ❋ Hugh Macmillan (N/A)
_Murrha_ was employed, which has been identified with fluor-spar, a translucent crystalline stone marked with blue, red, and purple, similar to the beautiful substance found near Matlock in Derbyshire. ❋ Hugh Macmillan (N/A)
The photo-electric excitability of fluor-spar crystals is increased by a moderate heat (80° to 100° C.). ❋ Various (N/A)
The most beautiful are those made of fluor-spar, the celebrated Blue John Mine providing the most beautiful specimens. ❋ Unknown (1900)
Fluorine is frequently met with as calcium fluoride or fluor-spar ❋ Cornelius Beringer (1886)
~Fluor~: fluor-spar as free as possible from other minerals, powdered. ❋ Cornelius Beringer (1886)
In the case of fluorides free from silicates (such as fluor-spar), it is determined indirectly by decomposing a weighed portion with sulphuric acid, evaporating, igniting, and weighing the residual sulphate. ❋ Cornelius Beringer (1886)
In these cases what we have is either a conversion of heat rays into light rays (as in the powdered fluor-spar), or the absorption and giving out again of sun-rays. ❋ Various (1880)
The diamond shines for a time in the dark after it has been exposed to the sun; so do pieces of quartz when rubbed together, and powdered fluor-spar when heated shines with considerable brilliancy. ❋ Various (1880)
Sullenly outstretched asleep it lay beneath us, coloured with the tints of fluor-spar, or with the changeful green and azure of a peacock's breast. ❋ John Addington Symonds (1866)
At its basement sleeps a pool, perfectly untroubled; a lakelet in which the sheltering rocks and nestling wild figs are glassed as in a mirror -- a mirror of blue-black water, like amethyst or fluor-spar -- so pure, so still, that where it laps the pebbles you can scarcely say where air begins and water ends. ❋ John Addington Symonds (1866)
I know not how many of you may be in the condition of this fluor-spar. ❋ John Tyndall (1856)
There are in the mineral world certain crystals -- certain forms, for instance, of fluor-spar, which have lain darkly in the earth for ages, but which nevertheless have a potency of light locked up within them. ❋ John Tyndall (1856)
Thus an ore containing a large proportion of fluor-spar may with great advantage be employed to flux another containing felspar or quartz, which substances are almost infusible alone. ❋ Various (1841)
The fluor-spar taken from this mine is of a rich blue color, and is wrought into vases and cups, which were extremely beautiful. ❋ William Cullen Bryant (1836)