Nepheline is the most abundant mineral of the feldspathoid group, which is abundantly found in the syenite igneous rocks of the volcanic eruption. Nepheline contains Sodium or Potassium with AlSiO4. Its chemical formula is (Na,K)AlSiO4. Some important physical properties of nepheline are as under;
- Physical Properties of Nepheline:
- It is vitreous greasy luster.
- It is found in a hexagonal crystal system.
- It is cut in poor cleavage. The cleavage is not so good.
- It has a specific gravity from 2.60 to 2.63.
- It is found naturally in white, grey, and yellowish colours.
- It is a mineral of massive habit.
- Its hardness is 5.5 to 6.0 on moh’s scale.
- It has transparent as well as opaque diaphaneity.
- Nepheline is the characteristic mineral of alkaline plutonic rocks, particularly nepheline syenites and nepheline gneisses.
- It is a mineral of brittle tenacity.
- Uses of Nepheline:
- It is used as a substitute for felspar for the manufacturing of glass and ceramics.
- Nepheline produced as a byproduct of apatite mining in the Kola Peninsula has found uses in ceramics, leather, rubber, textiles, wood, and the oil industry. It can be used as a filler in paints, plastics, and foam rubber, and has been investigated as an alternative to bauxite for aluminium manufacturing.
- Occurrence of Nepheline:
- Nepheline occurs in beautiful crystal form with mica, garnet, and sanidine feldspar on Monte Somma, Vesuvius, Italy.