hyalophane

{{Infobox mineral | name = Hyalophane | category = Tectosilicate minerals | group = Feldspar group | boxwidth = | boxbgcolor = | image = Hyalophane NHMLA.png | imagesize = | caption = Hyalophane crystal (Busovača, Bosnia and Herzegovina) | formula = | IMAsymbol = | IMAstatus = Grandfathered (1855), variety of microcline or orthoclase | molweight = 302.06 g/mol | dana = 76.1.1.3 | system = Monoclinic | class = Prismatic (2/m) | symmetry = C2/m (no. 12) | unit cell = a = 8.52 Å, b = 12.95 Å, c = 7.14 Å; β = 116°; Z = 4 | color = Colorless, yellow, white, red | habit = Crystalline – fine – occurs as well-formed fine sized crystals; massive – uniformly indistinguishable crystals forming large masses | twinning = Commonly simple twins according to the Carlsbad, Manebach, or Baveno laws | cleavage = {001} perfect, {010} imperfect | fracture = Conchoidal | tenacity = Brittle | mohs = 6 – | luster = Vitreous | polish = | refractive = nα = 1.542, nβ = 1.545, nγ = 1.547 | opticalprop = Biaxial (-) | birefringence = δ = 0.005 | dispersion = Weak | pleochroism = | fluorescence= | 2V = 48 – 79° | streak = White | gravity = 2.81 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent to translucent | other = | references = }}

Hyalophane or jaloallofane is a crystalline mineral, part of the feldspar group of tectosilicates. It is considered a barium-rich potassium feldspar. Its chemical formula is , and it has a hardness of 6 to . The name hyalophane comes from the Greek , meaning "glass", and meaning "to appear".