vigezzite

{{Infobox mineral | name = Vigezzite | category = Oxide mineral | image = Vigezzite-103199.jpg | caption = | formula = (Ca,Ce),(Nb,Ta,Ti)2O6 | IMAsymbol = Vgz | molweight = | system = Orthorhombic | class = Dipyramidal (same H-M symbol) | symmetry = Pnmb | unit cell = a = 11.065 Å, b = 7.527 Å c = 5.343 Å; α=90.00° β=90.00°, γ=90.00°; Z=4 | color = Orange-yellow | habit = Flat Prismatic crystals | twinning = | cleavage = Along {100} | fracture = conchoidal | tenacity = | mohs = 4.5-5 | luster = Sub Metallic | polish = | refractive = nα= 2.140 nγ= 2.315 | opticalprop = biaxial positive | birefringence = δ=0.175 | dispersion = extreme | pleochroism = | fluorescence= | absorption = | streak = | gravity = | density = 5.54 g/cm3 | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Subtranslucent to Opaque | other = | references = }}

Vigezzite is a variant of the mineral aeschynite containing calcium, cerium, niobium, tantalum, and titanium. It was first discovered near Orcesco, Valle Vigezzo, Provo Novara, Northern Italy, in cavities of an albitic rock. The crystals of Vigezzite are flat prismatic crystals up to 2-3 mm length of an orange-yellow color.The name Vigezzite was chosen to draw attention to the locality that has produced the first occurrence of a Ca-Nb-Ta-mineral with Nb dominance over Ta, crystallizing with the aeschynite structure. The ideal chemical formula for vigezzite is (Ca,Ce),(Nb,Ta,Ti)2O6