kidwellite

{{Infobox mineral|boxbgcolor=#64855e|boxtextcolor = #fff|image=Kidwellite-160225.jpg|formula=NaFe3+9+x(PO4)6(OH)4·12H2O (x ≈ 0.33)|IMAsymbol=Kdw|strunz=08.DK.20|system=Monoclinic|dana=42.08.02.01|class=Prismatic H-M Symbol: 2/m|symmetry=P2/c|unit cell=1,393.77|molweight=1,368.34|color=Greenish white, light green, greenish yellow, yellow|cleavage=Perfect on {100}|fracture=Splintery|mohs=3|luster=Resinous, waxy, silky, dull|opticalprop=Biaxial (−)|refractive=nα = 1.787 nβ = 1.800 nγ = 1.805|birefringence=0.018|pleochroism=None|dispersion=Extreme|fluorescence=None|streak=Yellow|gravity=3.04 – 3.3|density=Measured: 3.04 – 3.3 Calculated: 3.34|diaphaneity=Translucent|impurities=Aluminum, Copper, Arsenic}}

Kidwellite in an uncommon mineral that was discovered in Arkansas in the United States. It was approved by the IMA in 1974, but it was only named in 1978 by Moore and Ito after Albert Lewis (Laws) Kidwell.