hemimorphic crystal

[¦he·mē¦mȯr·fik ′krist·əl]

(crystallography)

A crystal with no transverse plane of symmetry and no center of symmetry; composed of forms belonging to only one end of the axis of symmetry.

References in periodicals archive ?

Wurtzite is known from the Francon quarry as a single specimen from the lower sill, with a dark brown, incomplete, hemimorphic crystal less than 2 mm across, associated with quartz, calcite and barite (GSC APS 721-1).

Habit A consists of barrel-shaped or hourglass-shaped, distinctly hemimorphic crystals with a hexagonal cross-section, elongated parallel to the c-axis, and ranging from 5 mm to, exceptionally, 6.5 cm in length.

Famous mineral localities: the Francon quarry, Montreal, Quebec

Large hemimorphic crystals to 1 x 1 cm were found perched on a layer of franckeite on Level 190 south of the Plata vein.

Famous mineral localifies: Llallagua, Bolivia

Donnayite-(Y) is extremely rare, and is found in cavities in the contact zone as crude, equant, opaque, beige to yellowish white hemimorphic crystals 0.5-1.0 mm in size, having a roughly hexagonal to circular cross-section, and dominated by a {001} basal pinacoid.