brianyoungite

{{Infobox mineral | name = Brianyoungite | category = Carbonate mineral | image = Brianyoungite-122711.jpg | imagesize = 260px | caption = Brianyoungite from Germany | formula = Zn3(CO3,SO4)(OH)4 | IMAsymbol=Byo | strunz = 5.BF.30 (10 ed) 5/C.01-105 (8 ed) | dana = 17.1.15 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/m | unit cell = 15.724 Å, b = 6.256 Å, c = 5.427 Å; β = 90°; Z = 4 | color = White | habit = Rosettes of thin blades, pseudo-orthorhombic with β close to 90° | twinning = | cleavage = Perfect on {100}, possible on {001} | fracture = | tenacity = | mohs = 2 to 2.5 | luster = Vitreous | refractive = nω = 1.635, nε = 1.650 | opticalprop = Biaxial | birefringence = δ = 1.635 | pleochroism = | streak = White | gravity = 3.93 to 4.09 | melt = | fusibility = | diagnostic = | solubility = Readily soluble with effervescence in acids | diaphaneity = Transparent to translucent | other = Non-fluorescent | references = }}

Brianyoungite is a secondary zinc carbonate mineral. The Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA) classifies it as a carbonate with the formula , but sulfate groups SO4 also occupy the carbonate CO3 positions, in the ratio of about one sulfate to three carbonates, so other sources give the formula as , and Gaines et al. classify the mineral as a compound carbonate. It is similar in appearance to hydrozincite, another zinc carbonate. It was discovered in 1991 and designated IMA1991-053. In 1993 it was named "brianyoungite" after Brian Young (born 1947), a field geologist with the British Geological Survey, who provided the first specimens.