Coimbra Exhibition

Bologna Stone

Place of OriginBologna, Italy
DateCollection date 19th century
DescriptionThis is a specimen of the so called "Bologna stone", first found in 1603 in Paderno, near Bologna. It is the first documented material to show persistent luminescence. This stone is made of baryte which, after a special process of heating in oxygen-free environment, radiates a characteristic reddish phosphorescence after being exposed to sunlight. The stone is part of the 19th century collections of the Cabinet of Natural History of the Institute of Science of Bologna.
TagsBologna stone; Luminescence; baryte; Alchemy:
Dimensionsdiameter 18 cm
Material/Mediumbarium sulfate
Institutional Link to Object
Institutional Link to Online Portal
Image LicenseCC-BY
Image Rights Holder© Copyright 2017 - ALMA MATER STUDIORUM - Università di Bologna
Photographic CreditsFrancesca Bargossi
Metadata RightsCC-O