- Division,
TRAPEZOHEDRAL class, FIG. 74.
Spencer 1911, p. 577, or p. 599 on Wikisource, CRYSTALLOGRAPHY, 2.
TETRAGONAL SYSTEM,
TRAPEZOHEDRAL class. Spencer...
- In geometry, the
trigonal trapezohedral honeycomb is a
uniform space-filling
tessellation (or honeycomb) in
Euclidean 3-space.
Cells are
identical trigonal...
-
trigonal β-quartz:
hexagonal Crystal class α-quartz:
trapezohedral (class 3 2) β-quartz:
trapezohedral (class 6 2 2)
Space group α-quartz: P3221 (no. 154)...
-
interest for its rare crystallography. It
crystallizes in the
tetragonal trapezohedral class and is one of only a few
minerals in that class.
Wardite forms...
-
Silica (silicon dioxide, SiO2)
Crystal system Trigonal Crystal class Trapezohedral (32)
Space group P3221 (no. 154)
Identification Color Purple, violet...
- described: type 1 –
elongated barrel-shaped; type 2 –
elongated with
trapezohedral facets; type 3 –
short cylindrical (Kostov, 2007; Kostov, Pelevina,...
- {\displaystyle \mathbb {Z} _{4}\times \mathbb {Z} _{2}} tetragonal-
trapezohedral D4
enantiomorphic 8
dihedral D 8 = Z 4 ⋊ Z 2 {\displaystyle \mathbb...
- 05 Dana
classification 75.01.03.01
Crystal system α-quartz:
trigonal trapezohedral class 3 2; β-quartz:
hexagonal 622
Space group Trigonal 32 Unit cell...
-
Strunz classification 3.BB.30
Crystal system Trigonal Crystal class Trapezohedral (32) H-M symbol: (32)
Space group P321 Unit cell a = 7.9, c = 3.95 [Å];...
- or
violet Crystal habit Usually m****ive; rare
crystals are
normally trapezohedral or
cubic Cleavage None
observed Fracture Conchoidal to
uneven Tenacity...
