Stellerite has a general formula of Ca

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

[Al₂Si

Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

₇O

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

₁₈]·7H

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

₂O. It is named after Georg Wilhelm Steller

Georg Wilhelm Steller

Georg Wilhelm Steller was a German botanist, zoologist, physician and explorer, who worked in Russia and is considered the discoverer of Alaska and a pioneer of Alaskan natural history.-Biography:...

 (1709–1746) who was a German explorer and zoologist that discovered it. Like most rare minerals, there aren’t many commercial uses for stellerite yet. Mineral collectors are lucky to find it in good enough crystal form. Zeolites, including Stellerite, have been studied using a dehydration process to gauge the potential use of their phases as molecular sieves, sorbents, and catalysts.

Crystal Habit

Stellerite is part of the orthorhombic crystal system which means it has three axes of unequal length that intersect at 90° angles. Its crystal class is rhombic-dipyramidal which means it has three perpendicular two-fold rotational axes with perpendicular mirror planes. This would look like a dipyramid cut horizontally along the middle to where the top and bottom halves each have four identical faces that can either be compared to the other faces by the 2-fold rotation axes or the mirror planes. Stilbite

Stilbite

Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named:*...

, another zeolite, is very similar to stellerite in both chemical composition and physical appearance. Stellerite is more commonly found in rounded radiating clusters or as single crystals and appears more transparent than stilbite does.

Optical Properties

Stellerite is an anisotropic mineral, meaning that it has different properties in different directions-such as indices of refraction-when light passes through it. A refractive index (n) measures the speed of light in a substance—or in the case of mineralogy—in a mineral. It is expressed as a ratio of the speed of light in a vacuum to that in a mineral. Stellerite has three indices of refraction because it is a biaxial mineral.

Occurrence

Stellerite lines cavities and fracture surfaces in volcanic rocks altered by hydrothermal solutions. Great examples of Stellerite are on Copper Island, Commander Islands (also discovered by Georg Steller), Bering Sea and at Klichka, Chita region, Siberia, Russia. In the United states, it is located at Ritter Hot Springs, Grant County, Oregon; on Hook Mountain, Rockland County, New York; and at Fanwood, Somerset County, New Jersey. Large crystals have been found in Australia around Gunnedah, New South Wales, and at Harcourt, Dookie, and Corop, Victoria.