Featured I came home today with this glazed and perforated block. What is it?

It's so heavy, I thought it was metal. But it's like ironstone or some other heavy pottery.

I thought it was a ventilation block for a building but didn't find anything in a search.

I've run out of things to think. What is it?
10" square and 2" thick.

 

Thank you! I was searching for vent brick among other things, but not air brick.

They also seem to be an English item.

 

https://www.pugin-tiles.com/decorated-bricks-and-airbricks

 

Don't you love when you bring something home that you know nothing about? I do it all of the time LOL

 

I'll buy a shelf lot, in this case, for a few items on the shelf. But finding out what the rest of the stuff is can be interesting. And, sometimes, the other stuff can be worth more than what you bought it for. This lot also had a pair of duck decoys. I assumed they were mass produced Chinese junk. Turns out they're signed by a local carver who's decoys can be worth decent money.

 

That’s a floor drain top, that is. Salt glazed stoneware. Doulton Lambeth made many.

 

Some of my best items have come from shelf lots where I paid no attention to items other than the ones I was after.

I bought a shelf lot many years ago for the plates that were there. I paid $17.50 for the shelf with the buyer's premium. I was packing the shelf & shrugged my shoulders when I saw the clear glass lantern globe shoved into a back corner.

I sold the plates for a nice profit & several weeks later I decided to check into the lantern globe. There was an embossed "ACL" on one side & I did figure out it was from a now-defunct rail line - Atlantic Coast Line.

I started the auction at $4.99 & a couple of days later it was up to about $500. A local guy contacted me to ask if he could see it in person. We met the next day at my booth & later that day I ended the listing because he offered me $2,200.00.

It turns out it was a globe from a short-lived Atlantic Coast Line railroad lantern circa late 1800s to early 1900s. He had the frame but it was missing the globe.

 

Awww I'm so happy for that guy!! And you, of course! It's so nice when the both of you can walk away pleased.

I too will zero in on something I want and go for it alone. If the bidding goes higher I might check the extra bit, but it's a nice surprise when you can get the thing AND a bonus!