In the central part of France lies a village called Pressac. There, on Holy Thursday, 1643, a mid-day Mass was said. Afterwards, a chalice containing one consecrated Host, as was the custom, was left on the altar covered by a veil. The altar consisted of a marble slab supported by four heavy wooden pillars.
Two hours later, fire could be seen coming from the church. When the people were able to inspect the damage, they found the marble slab on the ground. The four wooden pillars had been reduced to ashes. They also found remnants of the chalice. The upper portion had melted, but the base remained. Also, a thin bubble of metal was observed over the stem of the base. As the upper portion melted, it fell away to the sides, around the contents housed by the tin bubble, the consecrated Host.
The spectacle was seen by many, testimony was recorded and a declaration made of the miraculous event promptly made.
The Host was not preserved. As the next day was Good Friday, it was consumed during the service held then. A picture of the chalice, however, may still be seen. If you wish to do so, click on this link: http://www.therealpresence.org/eucharst/mir/english_pdf/Pressac.pdf.
Source: source: “The Eucharistic Miracles of the World,” a Vatican international exhibition, as reported by The Real Presence Eucharistic Adoration Association, http://www.therealpresence.org/eucharst/mir/engl_mir.htm.