adamite

{{Infobox mineral | name = Adamite | category = Arsenate mineral | boxwidth = | boxbgcolor =#70883a | boxtextcolor = #fff | image = Adamite-179841.jpg | caption = Yellow-green adamite in limonite | formula = Zn2AsO4OH |IMAsymbol=Ad | molweight = | strunz = 8.BB.30 | dana = 41.06.06.03 Olivenite group | system = Orthorhombic | class = Dipyramidal (mmm) H–M symbol: (2/m 2/m 2/m) | symmetry = Pnnm | color = Pale yellow, honey-yellow, brownish yellow, reddish; rarely white, colorless, blue, pale green to green, may be zoned | habit = Wedge-like prisms typically in druses and radiating clusters; also smooth botryoidal masses | twinning = | cleavage = {101}, good; {010}, poor | fracture = Uneven to subconchoidal | tenacity = Brittle | mohs = 3.5 | luster = Vitreous | refractive = nα=1.708 – 1.722, nβ=1.742 – 1.744, nγ=1.763 – 1.773 | opticalprop = Biaxial (+/−) | birefringence = δ = 0.055 | pleochroism = | streak = White to pale green | gravity = 4.32–4.48 measured | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = | other = May fluoresce and phosphoresce lemon-yellow under SW and LW UV. | references = }}

Adamite is a zinc arsenate hydroxide mineral, Zn2AsO4OH. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture. Tints of green also occur and are connected with copper substitutions in the mineral structure. Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called cuproadamite. Zincolivenite is an intermediate mineral with formula CuZn(AsO4)(OH). Manganese, cobalt, and nickel also substitute in the structure. Tarbuttite is an analogous zinc phosphate. thumb|left|Adamite on limonite from the Gold Hill District Tooele County, Utah, US. Scale at bottom is 2.5 cm.