johnbaumite

{{Infobox mineral | name = Johnbaumite | boxwidth = | boxbgcolor = | image = RM2040-roweita-johnbaumita-andradita.jpg | imagesize = | alt = | caption = | struct image = | struct caption = | struct imagesize = | struct2 image = | struct2 caption = | struct2 imagesize= | SMILES = | Jmol = | category = Apatite group | formula = Ca5(AsO4)3OH | IMAsymbol = Jbm | molweight = | strunz = 08.BN.05 | dana = 41.08.03.03 | system = Hexagonal | class = Dipyramidal (8/m) | symmetry = P63/m | unit cell = | color = | colour = Greyish white to colourless | habit = Anhedral grains, granular minerals without the expression of crystal shapes and massive, uniformly indistinguishable crystals forming large masses. | twinning = | cleavage = Distinct {1010} | fracture = Irregular/Uneven | tenacity = Brittle | toughness = | mohs = ≈ 4.5 | luster = Adamantine to greasy on fracture surfaces, vitreous on cleavage surfaces | streak = White | gravity = | density = 3.65 – 3.73 g/cm3 | polish = | opticalprop = Uniaxial (−) | refractive = nω = 1.687 nε = 1.684 | birefringence = 0.003 | pleochroism = Non-pleochroic | 2V = | dispersion = | extinction = Parallel | length fast/slow = | fluorescence = | absorption = | melt = | Curie temp = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent | impurities = | alteration = | other = | prop1 = | prop1text = | var1 = | var1text = | var2 = | var2text = | var3 = | var3text = | var4 = | var4text = | var5 = | var5text = | var6 = | var6text = | references = }}

Johnbaumite is a calcium arsenate hydroxide mineral. It was first described in 1980, where it appeared in Franklin, Sussex County, New Jersey. Johnbaumite was discovered at Harstigen mine in Sweden in the 19th century, but it was described as svabite.