Min. [ad. Ger. tachylit (Breithaupt, 1826), f. Gr. ταχύ-ς swift + λυτός soluble, in reference to its easy fusibility.] ‘A black basaltic glass, formerly regarded as a homogeneous mineral’ (Chester, Dict. Min.).
Tachylyte basalt, a variety of basalt having glassy selvages, and a highly microlithic basis.
1868. Dana, Min., 245. The species may be the same with tachylyte.
1879. Rutley, Stud. Rocks, x. 113. A proceeding analogous to that which seems to have taken place in some tachylytes.
1888. G. A. J. Cole, in Q. Jrnl. Geol. Soc., XLIV. 300. On some additional occurrences of Tachylite. Ibid. This tachylite adhered more firmly to the contact rocks than to the mass from which it was developed.
Hence Tachylitic, -lytic a., of the nature of, composed of, or containing tachylite.
1888. G. A. J. Cole, in Q. Jrnl. Geol. Soc., XLIV. 303. The vein … showed thin tachylitic selvage.
