The chemical formula of mineral Aegirine is indicated by NaFe(Si)2(O)6 or Sodium Iron Silicate. Aegirine is actually a Silicate mineral. The name of the mineral is of Greek origin. The alternate name Acmite was derived from a Greek word akme, meaning point. This is relative to the crystal shape of the mineral. The name Aegirine however, was derived from the name of a Teutonic or Scandinavian god of the sea, Aegir. The name Aegirine was given when the first specimens of this mineral were discovered in Norway. Aegirine is sometimes named as mineral Acmite in some other guides. The crystal formation of this mineral is of classic impression among collectors because it commonly exhibits nice and fascinating images under polarizing light microscope used in the field of optical mineralogy. This mineral is known as a member of the amphibole group with small maximum extinction angle and negative elongation when evaluated between crossed nicols of petrographic polarizing light microscope for mineralogists. Aegirine mineral forms crystal structures appearing to be steep, inclined pyramid sitting on top of prismatic crystals. A majestic view under a petrographic polarizing microscope for mineralogists as exhibited by its tall, monument-like crystals that are usually opaque in appearance, as they pop out splendidly from their host rocks.

 

            Aegirine exhibits a variety of splendid colors that appear more splendid when evaluated under a polarizing light microscope used in optical mineralogy. The colors shown may vary from black to greenish and sometimes brownish black when evaluated under geological polarizing microscopes. It commonly occurs in green or brown colors that can be splendidly exhibited under polarized light microscope. When viewed the mineral is viewed under petrographic polarizing microscope, a pleochroism from green to yellow green or from brown to greenish yellow is clearly visible. Mineral Aegirine is known to crystallize in the monoclinic system, which can be seen clearly when specimen is evaluated with the aid of polarized light microscope for geologists. In the field of optical mineralogy, the monoclinic system of crystal formation comprises crystals having three axes of unequal lengths. Two of which are usually found in a position that is oblique or not perpendicular to one another. However, both of which are commonly found perpendicular to the third axis. It can also be found with long prismatic crystal inclusion. The visibility of some steep-asymmetrical pyramid terminations is clearly visible when specimens are viewed under polarizing light microscopes used in optical mineralogy. Sometimes they may appear compact and fibrous, striated, or may be of disseminated grains, which are very interesting to view under polarized microscopes for mineralogists. It can also exhibit a splendid view under a polarizing microscope used in the field of optical mineralogy as those needle-like crystals took their appearance. 

 

            Aegirine mineral specimen is rubbed on a white porcelain streak plate, it is commonly found leaving a white and sometimes gray streak. The hardness measure of this mineral Aegirine when evaluated using the Mohs scale method is usually found ranging from 6 to 6.5 giving an average of 6.25. The specific gravity of mineral Aegirine is approximately 3.5 grams per cubic centimeters to 3.6 grams per cubic centimeters, which is considered above average for translucent minerals. It also exhibits a vitreous to resinous luster when viewed in reflected light of a polarizing microscope for mineralogists. The fracture formed when the mineral is examined under several adjustments on the aperture diaphragm of the polarized light microscope in optical mineralogy is usually uneven and sometimes crystals are considered brittle, a property commonly displayed by most non-metallic minerals. The cleavage found is commonly perfect in two directions at near 90 degree angle when viewed under a petrographic polarizing microscope used in the field of optical mineralogy.

 

            The Aegirine minerals display high surface relief when evaluated under petrographic polarizing microscope used in the field of optical mineralogy. And it also shows very strong birefringence when evaluated in plane-polarized light of petrographic polarizing light microscope for mineralogists. When viewed between crossed nicols of polarizing light microscope in optical mineralogy, Aegirine is usually found having a biaxial negative figure with a rather large axial angle. When viewed under a petrographic polarizing microscope used in optical mineralogy, these minerals exhibit a variety of interference colors. Mineral Aegirine is considered as a rather rare mineral. These kinds of mineral commonly occur in contact metamorphics. Sometimes they are also formed in Alkali Nepheline Syenites and other similar igneous rocks.