What is this?

[strife98]

So, my friend was running a couple of quarries on our server, and he found this at the bottom of one of them. What exactly is it?

[Euphoreich]

Wow, 25.1 M. You must be so heavy. How badly does it impact jetpack thrust?

Also that looks like a glitched water block.

[Calvariae]

It's a water spring from BuildCraft. I've found one too at the bottom of a shaft filled with water, but they seem to be slightly useless. They provide an infinite source of water, but it's not like infinite water is a particularly unique phenomenon in the Minecraft world.

Edit: Block id 521 if you were curious.

[Dash16]

Those stupid springs! You can't remove them with anything, and they cause the Buildcraft Filler to completely stop once encountered.

I hates them hobbitses.