epidote Min.
(ˈɛpɪdəʊt)
[a. Fr. épidote, f. as if on Gr. *ἐπιδοτός, f. ἐπιδιδόναι to superadd, f. ἐπί upon + διδόναι to give.
First used in Fr. by Haüy, who explains it as meaning lit. ‘qui a re{cced}u un accroissement’ (Minéralogie 1801. III. 112), and as denoting a great additional length in the base of the crystal as compared with that of certain allied minerals with which it was previously confused.]
A mineral common in many crystalline rocks, consisting largely of the silicate of iron and lime. It usually takes the form of flattened needles, and has a peculiar yellowish-green colour.
| 1808 T. Allan Minerals 2 Akanticone or Thallite, Epidote. 1879 Rutley Study Rocks x. 127 Epidote seldom gives direct evidence of its derivation from pyroxenic minerals. |
Hence epiˈdotic a., pertaining to or resembling epidote, containing epidote. ˌepidoˈtiferous a., bearing or containing epidote.
| 1849 Dana Geol. (1850) 565 The granitic and epidotic veins. 1862 ― Man. Geol. 76 An epidotic gneiss. 1884 Harper's Mag. 159/2 Veins of..epidotiferous quartz. |