Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 5, 2025
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. Several blocks of this material were found some years ago at the Marmorata which had been originally imported from Parthia in the reign of Hadrian.
When these crystals are warmed, the detent is lifted, and an outflow of light immediately begins." How often subtle analogies in physical nature whisper interpretations of vexing psychological enigmas? Was Erle Palma an animated, human fluor-spar?
Scientists tell us that "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. In their case the potential has never become actual, the light is, in fact, held back by a molecular detent.
The most beautiful are those made of fluor-spar, the celebrated Blue John Mine providing the most beautiful specimens. The purple shades present delightful tints, and some of the old workers in Derbyshire mosaics were exceptionally fortunate in their schemes of arrangement of the tiny pieces they inlaid so carefully.
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.
The spectroscope was formed entirely of fluor-spar, and a vacuum had been created in it, for these radiations are extremely absorbable by the air. Notwithstanding the extreme smallness of the luminous wave-lengths, it has been possible, after numerous fruitless trials, to obtain stationary waves analogous to those which, in the case of sound, are produced in organ pipes.
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. The depth appeared immeasurable. San Salvadore had receded into insignificance: the houses and churches and villas of Lugano bordered the lake-shore with an uneven line of whiteness.
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. This, then, is Petrarch's 'grotto; this is the fountain of Vaucluse.
This layer was formed of two plates of calcareous spar, which had evidently lined the opposite walls of a vertical cavity. The thirteen beds followed each other in corresponding order, consisting of fluor-spar, heavy spar, galena, etc. In these cases the central mass has been last formed, and the two plates which coat the walls of the rent on each side are the oldest of all.
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. The luminous paint which has recently attracted so much attention is of the same nature.
Word Of The Day
Others Looking