Name/Title
Cinnabar (twinned) on DolomiteEntry/Object ID
2023.7.31Description
About Cinnabar
Formula: HgS
Colour: Tint or shade of red; cochineal red, brownish red, silvery dark red; silvery-grey
Lustre: Metallic
Hardness: 2 - 2½
Specific Gravity: 8.176
Crystal System: Trigonal
Name: The origin of the name is still unclear, but beyond doubt oriental (Lüschen, 1979, p. 348).
The first name used for this mineral in a European lapidary, is the ancient Greek word "κιννάβαρι" (kinnàbari), mentioned by Theophrastus (c. 371 – c. 287 BC) in his treatise "Περὶ λίθων" (On Stones).
Polymorph of: Hypercinnabar, Metacinnabar
The α phase of HgS. Trimorphous with metacinnabar (the β phase) and hypercinnabar.
About Dolomite
Formula: CaMg(CO3)2
Ca can exist in excess of up to 0.25 apfu in non-stoichiometric dolomite (Nascimento dos Santos et al., 2017).
Colour: Colourless, white, gray, reddish-white, brownish-white, or pink; colourless in transmitted light
Lustre: Vitreous, Sub-Vitreous, Resinous, Waxy, Pearly
Hardness: 3½ - 4
Specific Gravity: 2.84 - 2.86
Crystal System: Trigonal
Member of: Dolomite Group
Name: Named in 1791 by Nicolas Théodore de Saussure in honor of the French mineralogist and geologist, Déodat (Dieudonné) Guy Silvain Tancrède Gratet de Dolomieu [June 24, 1750, Dolomieu, near Tour-du-Pin, Isère, France - November 26, 1801, Château-Neuf, Sâone-et-Loire, France]. de Dolomieu wrote numerous books on observations on geology, notably about the Alps and Pyrenees, in addition to theoretical books about the internal structure of the Earth. He discovered a specimen of what would eventually be called dolomite during his participation in Napoleon Bonaparte's expedition into Egypt in 1798.
Isostructural with: Nordenskiöldine
Dolomite Group. Ankerite-Dolomite Series.
Usually found as druzes or clusters of small rhombohedral crystals with a somewhat "saddle"-like shape, white to tan to pink in color.
For rocks also see dolostone.
Progressive dissolution–(re)crystallization reactions, leading to Ca-Mg cation ordering, are suspected to be responsible for Phanerozoic abundance of dolomite as compared to modern rock-forming environments (Pina et al., 2022).Location
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023