What is the chemical formula of nepheline?

What is the chemical formula of nepheline?

Nepheline
Formula (repeating unit)	(Na,K)AlSiO4
IMA symbol	Nph
Strunz classification	9.FA.05
Crystal system	Hexagonal

How is nepheline formed?

Nepheline only forms in silica-poor rocks. It is almost never associated with quartz. It may be found in some contact metamorphosed rocks otherwise it occurs in alkaline complexes in igneous rocks. Nepheline is mostly found in the rock Nepheline Syenite in nature.

What is nepheline used for?

Like feldspar, nepheline syenite is used as a flux in tile, sanitary ware, porcelain, vitreous and semi-vitreous bodies. It contributes high alumina without associated free silica in its raw form and fluxes to form silicates with free silica in bodies without contributing free silica itself.

What is the hardness of nepheline?

6.5
Nepheline syenite is a naturally occurring rock that consists mainly of the minerals albite, microcline and nepheline. This mineral raw material therefore contains no crystalline quartz; it is inert and is characterized in addition by a high degree of hardness (Mohs hardness 6.5).

Is nepheline a Pleochroic?

Nepheline does not exhibit twinning and has low birefringence as evidenced by the gray interference color of the central crystal in this image….Petrographic Data File.

Nepheline
Property	Value	Comments
Color/Pleochroism	Colorless in thin section (non-pleochroic)	.

Is nepheline an alkali feldspar?

Nepheline syenite is a pale-colored, coarse-grained rock composed essentially of alkali feldspar (ca.

How can you tell nepheline from quartz?

Resembles feldspars but nepheline is uniaxial, lacks good cleavage and twinning, and has a low birefringence. Nepheline is softer than quartz and differs in optic sign. Nepheline occurs in alkali-rich, silicon poor igneous rocks (nepeline syenite, foidite and phonolite).

How much does nepheline cost?

Nepheline Syenite (Minex) ~ 50 lbs

1 – 2	$23.40 as price per unit
3 – 10	$22.23 as price per unit
11 – 39	$21.06 as price per unit
40 – 999	$19.89 as price per unit

What type of rock is nepheline?

intrusive igneous rock
nepheline syenite, medium- to coarse-grained intrusive igneous rock, a member of the alkali-syenite group (see syenite) that consists largely of feldspar and nepheline. It is always considerably poorer in silica and richer in alkalies than granite.

Does nepheline have cleavage?

What is the melting point of nepheline?

Nepheline syenite begins melting around cone 1 and is one of the lowest melting feldspars.

Is nepheline length fast?

Longitudinal sections through elongate crystals are length fast. Resembles feldspars but nepheline is uniaxial, lacks good cleavage and twinning, and has a low birefringence. Nepheline is softer than quartz and differs in optic sign.

Is nepheline felsic or mafic?

alkaline mafic
Nepheline syenite is characterized by high ratio of (Na2O+K2O)/SiO2 and (Na2O+K2O)/Al2O3, which are represented respectively by the existence of nepheline and alkaline mafic minerals. Therefore, it is classified geochemically as alkaline rock.

Is nepheline syenite toxic?

Ingestion: No adverse effects expected for normal, incidental ingestion. Chronic Health Effects: Prolonged overexposure to any nuisance dust may cause lung injury. Symptoms include cough, shortness ofbreath, and reduced pulmonary function.

Is nepheline a gemstone?

Facetable nepheline is a great rarity, and very few gems have been cut, always in the 1-2 carat range or smaller. Name: From a Latin word meaning cloud because it becomes cloudy when immersed in acid….Nepheline Information.

Data	Value
Crystallographic Forms
Refractive Index	1.526-1.546

What does nepheline syenite do in a glaze?

Added to glazes, Nepheline syenite increases the firing range of low-fire and mid-range glazes. Nepheline Syenite can, however, incrase crazing in glazes due to its high thermal expansion. In ceramics, 270 mesh is the most common size used and has a medium melting and shrinking rate.

How can you tell the difference between quartz and nepheline?

Distinguishing Features Resembles feldspars but nepheline is uniaxial, lacks good cleavage and twinning, and has a low birefringence. Nepheline is softer than quartz and differs in optic sign.

What is nepheline syenite in paint?

Nepheline syenite is a micronized functional filler and extender used as a performance enhancer in a broad range of paints, coatings, adhesives, sealants, and inks. Excellent brightness, tint retention, and weatherability can be achieved in exterior paints.