1A solid figure whose faces are six equal rhombuses.

1. 1.1 A crystal or other solid object shaped like a rhombohedron.
   Example sentencesExamples

   • He arrived at this from a study of calcite crystals of various habits and noted that the cleavage rhombohedra were always the same.
   • Gilman pyrites typically have associated minerals, particularly flattened siderite rhombohedra and marmatite.
   • Several common carbonate minerals that form rhombohedra have been reported at the Lake George intrusive center: calcite, ferroan calcite, manganoan calcite, manganosiderite, rhodochrosite, and siderite.
   • At most locations in the Deccan Traps, the primary form for calcite is the rhombohedron.
   • These are nearly always accompanied by parallel overgrowth of several flattened rhombohedra aligned along each scalenohedron's c-axis, forming ‘pagodas’.
   • Colorless and transparent as well as white scalenohedra of a first generation are rarely overgrown by a second-generation rhombohedron and are twinned on { 0001 }.
   • Along this seam were occasional pockets from 0.1 to 0.5 meter across, lined with calcite rhombohedra.
   • This occurrence is known for plates of complex rhombohedra of pink manganoan calcite.
   • Specimens of slightly twisted, slightly curving chains of malformed, obtuse rhombohedra of calcite have been collected as specimens from the Cross vein.
   • A bit farther along the haulage tunnel from the chloritic quartz zone was an area containing plates of white quartz coated with a crust of strawberry-pink rhodochrosite rhombohedra.
   • Perhaps the best rhodochrosite specimen from this mining period, a lustrous, translucent red rhombohedron about 4 inches on edge, is now on exhibit in the Coors Mineral Hall of the Denver Museum of Natural History.
   • Rhodochrosite from the Sunnyside mine generally forms pale pink to strawberry-pink simple rhombohedra on plates of drusy white quartz.
   • This Eagle mine is well known for dark spruce-green, rough-surfaced octahedra of fluorite associated with rhombohedra of rhodochrosite to 0.75 inch on edge.
   • At the Lower East Fork locality nontronite was observed as brownish-black spherules, 0.6 mm in diameter, perched on microcrystals of quartz associated with calcite rhombohedra.
   • Faceted stones weighing 25.56 and 61.24 carats along with a rhombohedron of rhodochrosite on matrix are illustrated and discussed by Sinkankas.
   • It commonly forms large, perfect rhombohedra that are cherry-red, strawberry-pink, or pale pink in color.
   • The Henderson mine also contains sharp octahedra of pale grass-green fluorite to 1.25 inches on edge, but generally much smaller, that are commonly associated with pale pink rhodochrosite rhombohedra to about 0.25 inch.
   • Access to the pit is prohibited, but excellent specimens of calcite scalenohedra, dolomite rhombohedra, pyrite, and marcasite have been collected from the pit's east wall.
   • Rhodochrosite crystals do occur here from time to time as relatively small flat rhombohedra.
   • Sharp, clear magnesite rhombohedra may be mistaken for ‘Iceland spar’ calcite, but the density is a quick tip-off to the mineral's true identity.