Geeking out over Crystals in Limewater

We left some old limewash samples sitting in their little cups in the back corner of our office about 2 weeks ago, and I have been slowly watching the Calcite Crystals form a nice little brittle layer on top of the limewater. How’s that for watching paint dry?! When limewash sits for a while, it separates into “curds” (the lime putty at the bottom) and “whey” (the limewater on top). Recent articles have shown that conservators can actually use this type of limewater as a consolidant over deteriorating plaster and even artistic frescoes! That’s really cool. However, the limewater apparently takes about 80 Days to achieve any consolidation effect. Regular ole chemical consolidants that you can purchase ready-made achieve their effect in about 14 days, for comparison. I’ve noticed that the limewater crystals are forming at slightly different rates depending on which pigments were added to the mixture. Greens and blues seem to be forming the fastest. However, the speed of crystal formation doesn’t seem to be directly related to the strength of the crystal formation. We have cups of limewash that include red iron oxide pigments, and they are also developing calcite crystals on top of the limewater, just at a slower rate. It’s funny how blue is always faster than red in the natural world.

Enough geeking out over crystal formation for one day. Back to work!