Webster’s Revised Unabridged Dictionary · 1913
Blue-john
Blue′-john′ (·jŏn′), n. A name given to fluor spar in Derbyshire, where it is used for ornamental purposes.
Webster’s Revised Unabridged Dictionary · 1913
Blue′-john′ (·jŏn′), n. A name given to fluor spar in Derbyshire, where it is used for ornamental purposes.