This yellowish white - blue speckled piece of glass was only a few days ago a beautiful yellow green piece of glass with firebrick throughout!!!!!!! What the heck happened? it was a chunk left over from the local glassworks of the 1800's, and i placed it in some toilet bowl cleaner like I do with all my insulators. There was another bottle in the acid too. Out pops this thing, It was all blue. After putting it under the water the blue fell off. This coating is almost like talc in its solid state. After some scraping I've revealed that there is some glass left, but its a lot smaller than before. Any body tell me what the heck made this chemical reaction occur???? Also, do you think the powder is dangerous. the toilet bowl cleaner is Hydrochloric Acid.