kurnakovite

{{Infobox mineral | name = Kurnakovite | boxwidth = | image = Kurnakovite-mrz200a.jpg | alt = | caption = Kurnakovite from Boron, California | category = Nesoborates | formula = MgB3O3(OH)5·5H2O | IMAsymbol = Kko | molweight = | strunz = 6.CA.20 | dana = | system = Triclinic | class = Pinacoidal () (same H-M symbol) | symmetry = P | unit cell = a = 8.3479(1) b = 10.6068(1) c = 6.4447(1) [Å] α = 98.846°, β = 108.981° γ = 105.581°; Z = 2 | color = White; colorless in transmitted light | colour = | habit = Aggregates of prismatic crystals | twinning = Twinning uncommon | cleavage = Poor to indistinct on {010} | fracture = | tenacity = | mohs = – 3 | luster = Vitreous | streak = White | diaphaneity = Transparent to translucent | gravity = 1.847 – 1.852 | density = | polish = | opticalprop = Biaxial (-) | refractive = nα = 1.488 – 1.491 nβ = 1.508 – 1.510 nγ = 1.515 – 1.525 | birefringence = δ = 0.027 – 0.034 | pleochroism = | 2V = Measured: 60° to 80° | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = }}

Kurnakovite is a hydrated borate of magnesium with the chemical composition MgB3O3(OH)5·5H2O. It is a member of the inderite group and is a triclinic dimorph of the monoclinic inderite.