rhombohedral, a.
(rɒmbəʊˈhiːdrəl)
[f. next + -al1.]
Pertaining to or having the form of a rhombohedron; Cryst., denoting a system in which all the forms are derivable from the rhombohedron; also, belonging to this system.
| 1830 H. J. Brooke in Encycl. Metrop. (1845) VI. 432/1 The rhombohedral [system of Mohs] consists of the rhomboid. 1837 Whewell Hist. Induct. Sci. (1857) II. 293 The rhombohedral calc-spar; or..Iceland spar. 1854 [see next]. 1881 Nature XXIV. 355 Prof. Tschermak has adopted the four⁓plane axial system in the rhombohedral system. |
So rhombohedric (-ˈhɛdrɪk), a.
| 1854 Pereira's Polarized Light 165 The rhombohedric or rhombohedral system. 1855 J. Scoffern in Orr's Circ. Sci., Elem. Chem. 77 Crystals not having 3 rectangular axes... Rhombohedric, Pyramidal, Prismatic. |