rhombohedron

1 In reaction process P-zeolite first appears the short column crystal and then the crystal pattern changes from short column to rhombohedron with reaction time lasting.

在反应过程中，P沸石首先呈短柱状结晶，随着反应时间延长，结晶形态发生变化，由短柱状向菱面体过渡。

2 Calcite cleaves in three directions parallel to the faces of the primitive rhombohedron.

3 Chalybite crystallizes in the rhombohedral system and is isomorphous with calcite; like this it possesses perfect cleavages parallel to the faces of the primitive rhombohedron, the angles between which are 73� 0′.

4 The crystals have the form of a hexagonal prism m terminated by a rhombohedron r, the alternate edges between these being sometimes replaced by the faces of a rhombohedron s.

5 As in the other rhombohedral carbonates, the crystals possess perfect cleavages parallel to the faces of the rhombohedron.

6 The end faces are cut off in such a manner that the angle of 72� which they originally form with the lateral edge of the rhombohedron is reduced to 68�.

7 The zig-zag lateral edges coincide with the similar edges of a rhombohedron, as shown in fig.

8 Haydenite is the name given to small yellowish crystals, twinned on a rhombohedron plane r, from Jones’s Falls near Baltimore in Maryland.

9 Six kinds of primitive forms were distinguished, namely, the cube, the regular octahedron, the regular tetrahedron, a rhombohedron, an octahedron with a rhombic base, and a double six-sided pyramid.

10 In calcite, for instance, the figure has roughly the shape of a rounded rhombohedron with depressed faces and is symmetrical about three vertical planes.

1 菱面体

rhombus rhomb rhombohedral

2 菱形六面体

rhombus rhomb

3 斜方六面体

rhombohedral rhomb