What is this data
If a brick is flammable, if it was burnt, if it's blazing, its edible values, its properties values, its dryness values, its impurities values, its wetting modifications, its purifying modifications, and so on and so on.
where does it come from
When the brick is placed.
why do you want to store it
To be able to reboot the server without players losing their progress.
how do you want to store it
.bls files.
wtf do bls files have to do with this
"Save Bricks"
etc...
Etc.
"object variables are inefficient"
"why can't I store it in strings instead"
This is completely the wrong direction to go in if you care about performance.
The name string is stored by Blockland, requiring no effort in my part. On the other hand, to easily store all of the data without a salad, I would need to use arrays.