plagioclastic, a. Min.
(-ˈklæstɪk)
[f. plagio- + Gr. κλαστ-ός broken, cloven + -ic.]
Having oblique cleavage. Opp. to orthoclastic.
| 1869 Geikie in Edinb. Geol. Soc. Jrnl. II. 5 Plagioclastic felspars. 1879 Rutley Stud. Rocks x. 91 The plagioclastic..or those in which the cleavage planes intersect at angles other than 90°. 1895 Syd. Soc. Lex., Plagioclastic, breaking obliquely. |