Commonly as euhedral, pseudocubic crystals; rarely granular, massive
Twinning
Common and repeated on {110} and {101}
Cleavage
Poor on {110}
Fracture
Conchoidal
Tenacity
Brittle
Mohs scale hardness
5.5–6
Luster
Vitreous
Streak
White
Diaphaneity
Transparent to translucent
Specific gravity
2.45–2.50
Optical properties
Uniaxial (+)
Refractive index
nω = 1.508 nε = 1.509
Birefringence
δ = 0.001
References
[2][3]
Leucite (from the Greek word leukos meaning white) is a rock-forming mineral of the feldspathoid group, silica-undersaturated and composed of potassium and aluminium tectosilicate KAlSi2O6.[4] Crystals have the form of cubic icositetrahedra but, as first observed by Sir David Brewster in 1821, they are not optically isotropic, and are therefore pseudo-cubic. Goniometric measurements made by Gerhard vom Rath in 1873 led him to refer the crystals to the tetragonal system. Optical investigations have since proved the crystals to be still more complex in character, and to consist of several orthorhombic or monoclinic individuals, which are optically biaxial and repeatedly twinned, giving rise to twin-lamellae and to striations on the faces. When the crystals are raised to a temperature of about 500 °C they become optically isotropic and the twin-lamellae and striations disappear, although they reappear when the crystals are cooled again. This pseudo-cubic character of leucite is very similar to that of the mineral boracite.
The crystals are white or ash-grey in colour, hence the name suggested by A. G. Werner in 1701, from λευκος, '(matt) white'. They are transparent and glassy when fresh, albeit with a noticeably subdued 'subvitreous' lustre due to the low refractive index, but readily alter to become waxy/greasy and then dull and opaque; they are brittle and break with a conchoidal fracture. The Mohs hardness is 5.5, and the specific gravity 2.47. Inclusions of other minerals, arranged in concentric zones, are frequently present in the crystals. On account of the color and form of the crystals the mineral was early known as 'white garnet'. French authors in older literature may employ René Just Haüy's name amphigène, but 'leucite' is the only name for this mineral species that is recognised as official by the International Mineralogical Association.
Leucite (from the Greek word leukos meaning white) is a rock-forming mineral of the feldspathoid group, silica-undersaturated and composed of potassium...
olivine. Unless potash is high and silica relatively low, leucite will not be present, for leucite does not occur with free quartz. Nepheline, likewise, is...
Leucitite or leucite rock is an igneous rock containing leucite. It is scarce, many countries such as England being entirely without them. However, they...
Minerals typical of lamproites include: forsteritic olivine; high iron leucite; titanium-rich aluminium-poor phlogopite; potassium- and titanium-rich...
evolves through trachybasalt or leucite trachybasalt through tristanite or leucite tristanite to potassic trachyte or leucite phonolite. The nephelinic, leucitic...
porphyritic texture. Mineral content is usually abundant feldspathoids (leucite or nepheline), plagioclase, and lesser alkali feldspar. Pyroxenes (clinopyroxenes)...
is a variation of the igneous rock trachyte that contains nepheline or leucite rather than quartz. It has an unusually high (12% or more) Na2O + K2O content...
glass-based systems (mainly silica) with fillers, usually crystalline (typically leucite or, more recently, lithium disilicate) Composition category 3 – crystalline-based...
The mineral is not radioactive. Haüyne occurs in phonolites and related leucite- or nepheline-rich, silica-poor, igneous rocks; less commonly in nepheline-free...
nepheline syenites have to the phonolites. A leucite-augite rock, resembling ijolite except in containing leucite in place of nepheline, is known to occur...
(KAlSi3O8) produces leucite (KAlSi2O6) in addition to a melt. The melt produced is richer in silica (SiO2). The proportions of leucite and melt formed can...
1797. As soon as Martin Klaproth discovered the presence of potassium in leucite and lepidolite, Vauquelin demonstrated that common alum is a double salt...
contains nepheline-alkali feldspar pseudomorphs interpreted to be after leucite which occur as conspicuous white spots in the dark rock matrix. The rock...
Tusk is an isolated remnant of a long extinct volcano associated with the Leucite Hills to the east. Heavily eroded, all that remains of the volcano is part...
compared to augite in tholeiitic basalt. Minerals such as alkali feldspar, leucite, nepheline, sodalite, phlogopite mica, and apatite may be present in the...
the German chemist Martin Klaproth discovered "potash" in the minerals leucite and lepidolite, and realized that "potash" was not a product of plant growth...
it is a diopside-leucite phlogopite lamproite. It is a potassium enriched, alkaline, basic, phonolite first found in the Leucite Hills of Sweetwater...
Martin Klaproth discovered the presence of potassium in the minerals leucite and lepidolite. Louis Vauquelin then conjectured that potassium was likewise...
Diodorus Unknown consorts Agylleus Amathous Azon Chromis Cyrnus Dexamenus Leucites Manto Pandaie Phaestus or Rhopalus In Rome, Heracles was honored as Hercules...
Bassani (1853–1916). At Vesuvius it occurs as alterations from gypsum within leucite tephrite and as fumarole deposits. It occurs in dry lake beds in California...
Feldspathoid mineral Kalsilite – Vitreous white to grey feldspathoidal mineral Leucite – Potassium and aluminium tectosilicate mineral Nepheline – Silica-undersaturated...
in volcanic rock. The same distinction holds for nepheline varieties. Leucite is common in lavas but very rare in plutonic rocks. Muscovite is confined...
Norbert; Frankenberger, Roland (March 2005). "Clinical performance of bonded leucite-reinforced glass ceramic inlays and onlays after eight years". Dental Materials...
occurs in association with orthoclase, sanidine, labradorite, olivine, leucite, amphiboles and other pyroxenes. Occasional specimens have a shiny appearance...
with other minerals typical of silica-undersaturated environments, namely leucite, cancrinite and natrolite. Other associated minerals include nepheline...
as for foid-bearing gabbro, so that a gabbroid might be classified as a leucite-bearing monzogabbro. Gabbroids contain minor amounts, typically a few percent...
Retrieved 2007-11-20. Hausel, W. Dan (2006). Geology and Geochemistry of the Leucite Hills Lamproitic field, Rocks Springs Uplift, Wyoming. laramie, Wyoming:...
Global Information