fluorsparn.

?1770 J. Warltire Conc. Ess. Philos. & Chem. Subj. 51 Fluor spar reduced to the fineness of coarse sand, and covered with vitriolic acid, with a lamp heat yields an air that corrodes glass.

1798 G. Mitchell tr. D. L. G. Karsten Descr. Minerals in Leskean Mus. I. 7 Somewhat lighter, violet blue Fluorspar, inclining to black at the edges..from Augustusburg in Saxony.

1812 H. Davy Elements Chem. Philos. 465 A substance found abundantly in nature called fluor spar, it is usually either blue, green, yellow, or white, transparent, and crystallized in cubes.

1863 E. Atkinson tr. A. Ganot Elem. Treat. Physics vii. vii. 465 The best phosphorescents are..diamonds..fluorspar [etc.].

1880 D. T. Ansted In Search of Minerals 18 The crystal of fluor-spar has the striæ parallel all round the four sides.

1938 R. Hum Chem. for Engin. Students xxii. 604 Calcium Fluoride..occurs naturally as fluorspar and as a coloured form, Blue John, the colour probably being due to organic impurity.

1978 H. E. L. Andrew Batsford Encycl. of Crafts (1988) 221/1 Semi-precious stones..such as..the very beautiful Blue John (fluorspar) from Derbyshire.

1989 Holiday Which? May 142/2 Scars of the lead and fluorspar mines show there is profit under the landscape.

2001 O. Sacks Uncle Tungsten xxi. 262 Uncle Abe showed me a piece of fluorspar which he had exposed to radium for several days.