This video shows a seashell being heated to 800℃ using a halogen point heater.
Please check the following site for more information.
Related page:
Heating of emerald (Nanosital) 
Pinpoint heating of 0.5mm mechanical pencil lead 
Heating of the tile 
Heating of the refractory brick 
Heating purified water on a silicon wafer 
Heating, melting and vitrification of rocks series 23 – Sandstones 
Heating, melting and vitrification of rocks series 26 – Chalcopyrite 
Heating, melting and vitrification of rocks series 7 – Basalt