stellerite

{{Infobox mineral | name = Stellerite | category = Tectosilicate minerals | group = Zeolite group, stilbite subgroup | boxwidth = | boxbgcolor = | image = Stellerite - Takat, Imilchil, Midelt Province, Drâa-Tafilalet Region, Morocco.jpg | imagesize = 270px | caption = | formula = Ca(Al2Si7O18)·7H2O | IMAsymbol = Ste | molweight = | strunz = 9.GE.15 | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = Fmmm | unit cell = | color = Colorless to white, pink, orange | habit = Spherical, Stellate, Tabular | twinning = | cleavage = Perfect on {010} | fracture = Uneven | tenacity = | mohs = 4.5 | luster = Pearly | refractive = | opticalprop = Biaxial (-), a=1.4848, b=1.4864-1.4964, g=1.4979 | birefringence = δ = 0.013 | pleochroism = | streak = white | gravity = approximately 2.2 | density = 2.13 g/cm3 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent to translucent | other = | references = }}

Stellerite is a rare mineral discovered by and named after Georg Wilhelm Steller, a German explorer and zoologist. The mineral has a general formula of Ca[Al2Si7O18]·7H2O. Like most rare minerals, there are few commercial uses for stellerite. 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. Its occurrences are in cavities of andesite as sheaf-like clusters of small crystals.