a. [f. as prec. + -OID, after F. trachytoïde.] Resembling or allied to trachyte.
1885. Geikie, Text-bk. Geol., II. II. v. (ed. 2), 110, note. For this [semi-crystalline] structure the term ‘mixed’ has been proposed, as being a mixture of the crystalline and amorphous (glassy) structures. It has been designated by Fouqué and Michel-Lévy ‘trachyloid,’ as being typically developed among the trachytes. Ibid., vii. 137. Two leading types of structure are recognised by these authors among the eruptive rocks. 1. Granitoid…. 2. Trachytoid, distinguished by a more marked contrast between the crystals of the first and second consolidation, the usual presence of an amorphous magma, and the fluxion structure.
