The Bologna Stone: history's first persistent luminescent material

Research output: Contribution to journalArticle


In 1603, the Italian shoemaker Vincenzo Cascariolo found that a stone (baryte) from the outskirts of Bologna emitted light in the dark without any external excitation source. However, the calcination of the baryte was needed prior to this observation. The stone later named as the Bologna Stone was among the first luminescent materials and the first documented material to show persistent luminescence. The mechanism behind the persistent emission in this material has remained a mystery ever since. In this work, the Bologna Stone (BaS) was prepared from the natural baryte (Bologna, Italy) used by Cascariolo. Its properties, e. g. impurities (dopants) and their valences, luminescence, persistent luminescence and trap structure, were compared to those of the pure BaS materials doped with different (transition) metals (Cu, Ag, Pb) known to yield strong luminescence. The work was carried out by using different methods (XANES, TL, VUV-UV-vis luminescence, TGA-DTA, XPD). A plausible mechanism for the persistent luminescence from the Bologna Stone with Cu+ as the emitting species was constructed based on the results obtained. The puzzle of the Bologna Stone can thus be considered as resolved after some 400 years of studies.


  • Mika Lastusaari
  • Taneli Laamanen
  • Marja Malkamaki
  • Kari O. Eskola
  • Aleksei Kotlov
  • Stefan Carlson
  • Edmund Welter
  • Hermi F. Brito
  • Marco Bettinelli
  • Hogne Jungner
  • Jorma Holsa
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Natural Sciences
  • Physical Sciences


  • Persistent luminescence, Bologna Stone, baryte, copper, barium sulphide, XANES, thermoluminescence, thermogravimetry, differential thermal, analysis, X-ray powder diffraction
Original languageEnglish
Pages (from-to)885-890
JournalEuropean Journal of Mineralogy
Issue number5
Publication statusPublished - 2012
Publication categoryResearch