Home of The Stone Detective
The Case Of The Perfect Circles
The rain had been falling since midnight, turning the street outside Flo’s Diner into something fit for an old detective movie. I parked my 1946 Ford Woody in its usual spot and took the third stool from the end. Flo poured me a cup of coffee while the Admiral sat in his booth telling a story about surviving a Pacific typhoon.
“You look wet,” Flo said.
“It’s raining.”
“I hadn’t noticed.”
Before I could flirt my way into a second cup, the phone behind the counter rang.
Flo answered it, listened, then handed it to me.
“A woman says circles are appearing in her kitchen.”
“Stone Detective here.”
A Call About Circles
The caller had recently installed quartzite countertops. Several dark, perfectly round marks had appeared shortly afterward. Cleaning didn’t remove them, and another coat of sealer only made them disappear temporarily.
Perfect circles are rarely an accident.
I left my eggs cooling on the counter, climbed into the Woody, and headed to the scene.
The Scene at the Countertop
The countertop was beautiful, except for six dark circles spread across the island and surrounding tops. They were nearly identical in size.
I examined them under reflected light. The surface wasn’t scratched or etched. The marks appeared to be within the stone.
“Do they darken when the countertop gets wet?” I asked.
“Yes,” the homeowner replied.
There was my first real clue.
Cracking the Case
The circles matched the suction cups used to lift and move the slabs. These cups can trap moisture or transfer oils and plasticizers into porous stone. Since the quartzite had been wet-cut and sealed before it had completely dried, moisture became trapped beneath the surface.
The second coat of sealer only slowed the drying process.
I recommended:
- Applying no more products
- Giving the countertop time to dry
- Using fans and dehumidification to help
- If circles remained after drying, using a properly tested poultice to remove any residue transferred from the suction cups
Case Closed
When I returned to the diner, Flo poured me another cup of coffee.
“So, what caused the circles?” she asked.
“Suction cups used to lift the stone.”
The Admiral looked up.
“We used suction cups in the Navy.”
“Of course you did,” I said.
Flo slid my cold eggs back in front of me.
The case was closed. The circles weren’t mysterious stains. They were fingerprints left behind by the equipment used to handle the slabs.
Another case solved, and another breakfast sacrificed in the name of stone justice.
