gugiaite

{{Infobox mineral | name = Gugiaite | image =Gugiaite Baveno-1.jpg | category = Sorosilicate | alt = | caption = | formula = | IMAsymbol = Gug | strunz = 9.BB.10 | dana = 55.04.02.06 | system = Tetragonal | class = Scalenohedral (2m) H-M symbol: ( 2m) | symmetry = P21m | unit cell = a = 7.43, c = 5.024 [Å]; Z = 2 | molweight = | color = Colorless | colour = | habit = | twinning = | cleavage = Perfect on {010}, distinct {001}, indistinct on {110} | fracture = Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern | tenacity = | mohs = 5 | luster = Vitreous, glassy | streak = White | diaphaneity = Transparent | gravity = | density = 3.03 | polish = | opticalprop = uniaxial (+) | refractive = nω = 1.664 nε = 1.672 | birefringence = δ = 0.008 | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = strongly piezoelectric | references = }}

Gugiaite is a melilite mineral, named for the Chinese village of Gugia where it was first discovered. Its chemical formula is . It occurs mostly in skarns with melanite adjacent to an alkali syenite and has no economic value. Its crystals are small tetragonal tablets with vitreous luster and perfect cleavage. It is colorless and transparent with a density of three. The mineral belongs to space group P21m and is strongly piezoelectric.