“Incredibly rare” ancient purple dye that was once worth more than gold found in U.K. CBS News‘Mysterious’ purple lump found at ancient Roman ruins was once ‘worth more than gold’ Yahoo! VoicesRoman snail dye found in UK for the first time BBC.comArchaeologists discover prized purple pigment in Roman bath-house near Hadrian’s Wall The TelegraphFirst Ever Solid Fragment of Tyrian Purple, the Expensive Pigment Associated with Roman Emperors, Found LBV Magazine