ROCKBRIDGEITE Greenbelt (Prince Georges County), Harvard Mineralogical Museum Collection, Jake Slagle photographer

"LAUBMANNITE" discredited, actually PHOSPHATE COMBINATION Greenbelt (Prince Georges County), Jake Slagle Collection, Jake Slagle photographer

GYPSUM (var.) SELENITE Fort Washington (Prince Georges County), Jake Slagle Collection, Jake Slagle photographer

GYPSUM on SIDERITE Muirkirk Iron Ore Banks (Prince Georges County), Jake Slagle Collection, Jake Slagle photographer

VIVIANITE Wheeler Roadcut (Prince Georges County), Harvard Mineralogical Museum Collection, Jake Slagle photographer

VIVIANITE Wheeler Roadcut (Prince Georges County), Jake Slagle Collection, Jake Slagle photographer