Quote Originally Posted by Mike Kennedy
Just picked up 4lbs. of cat litter made with 100% silica (the blue stuff that changes color)
[font=Arial][font=Verdana]Silica gel is transparent by itself. An indicator known as cobalt chloride is often added (0.5% to 1%), it is this chemical that turns from blue to pink when saturated. [/font][/font][font=Arial][font=Verdana]Make sure you don't breath the dust from this silca gel as it could be cancer causing ![/font][/font]

[font=Arial][font=Verdana]In July 2000, European Directive No67/548/EEC 'reclassified' cobalt chloride to a Category 2B (proven animal carcinogen and therefore possibly carcinogenic to humans).[/font] [/font]
http://www.envirogel.co.uk/faq.htm
http://www.cr.nps.gov/museum/publica...gram/02-15.pdf
http://www.geejaychemicals.co.uk/cobaltchloride.htm
http://en.wikipedia.org/wiki/Silica_gel

regards
Peter