Frederick M. Hueston, PhD

Continued from the May Slippery Rock Gazette

The Stone with the BluesI know most of you are dying to find out what caused that blue discoloration I described in last month’s column. Well, folks – the wait is over. Hold on to your hat. If you guessed right, drop me a line, because you have bragging rights!

In general, blue discoloration in any stone can be the result of stains from blueberries, plant food, ink, and more.  But in this case, the blue discoloration was coming from the setting mortar. More specifically, I found the epoxy mortar – that was blue in color – was the culprit. I have seen this on two other occasions, and it’s a reaction that takes place with the combination of Part A and Part B. This usually happens when the epoxy is out of date… in other words, like me, it’s old! 

Mystery solved. Click here for this month’s mystery.