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Stellerite Ball in Matrix
SILICATES; TECTOSILICATES; ZEOLITE GROUP · ORTHORHOMBIC

Stellerite

CaAl2Si7O18 · 7(H2O)

Hardness
4–4.5
Streak
Colorless
Spec. Gravity
2.1–2.2
System
Orthorhombic

About

Stellerite is an uncommon member of the zeolite group, and is very similar in structure and formation to Stilbite. Stellerite is named after Georg Wilhelm Steller (1709–1746) a famous German explorer, physician, and zoologist. Steller first discovered this mineral on the Commander Islands (also known as the Komandorski Islands) in far east Russia. Aside from being the first to explore these islands and discover this new mineral, Steller is also credited for identifying several animal species that were named after him, such as the steller's sea lion, and the now-extinct steller's sea cow.

Crystal Forms & Aggregates

Most often as rounded, radial groups. The groups can be clustered together or in separate balls, and may form as perfectly rounded formations. Also in platy aggregates, and in distinct curved aggregates of fan-shaped, wheat sheaf, or bow-tie bundles. Individual crystals, which are rare, are in flat tabular crystals with pointed tips.

Striking Features

Crystal habits and mode of occurrence

Environment

Uses

Stellerite is an uncommon mineral that is highly desired by collectors. Its only practical use is as specimen for collectors, especially zeolite collectors.

Noteworthy Localities

Although Stellerite is uncommon, it is present in some of the important zeolite deposits and can be mistaken for the much more common Stilbite. Only the significant occurrences will be mentioned here.

Bright orange Stellerite in large crystal groups are well-known from the Sarbaiskoe (Sarbai) and Sokolovskiye Mines, Kostanay Province, Kazakhstan. Large and beautiful crystals occur in several of the famous zeolite localities in Maharashtra, India, including Pune (Poona), Jalgaon, Aurangabad, Nasik. In Australia, large, individual, peach-colored Stellerite crystals come from Garrawilla, Gunnedah, and Tambar Springs, all in Pottinger Co., New South Wales. Yellow Sterllerite comes from Malmberget, Lappland, Sweden; and white microcrystals from Gibelbach, Fiesch, Switzerland.

In the U.S., the most significant locality is the Braen's Quarry, Haledon, Passaic Co., New Jersey, where the Stellerite has been found in lustrous colorless rounded balls. Small yellow Stellerite spheres come from the Kibblehouse Quarry, Perkiomenville, Montgomery Co., Pennsylvania; and white clusters from the Dyer Quarry, Gickerville, Birdsboro, Berks Co., Pennsylvania. Rounded Stellerite plates have come from Ritter Hot Springs, Grant Co., Oregon.

Common Mineral Associations

Distinguishing Similar Minerals

Stilbite - Often more rounded and glossy; otherwise very difficult to distinguish.

Photos

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