What is this stone?

[Ben]

I found this stone on a beach about an hour south from surfers paradise a couple years ago and was wondering if anyone might know what it is?..

 

[Ben]

 

[AtomRat]

Looks a bit like an agate or even chert / flint. Its an odd one though as it also resembles potch.

 

[Phoenix76]

Hard to tell Newbie, but must agree with AtomRat that it looks like agate. The Gold Coast hinterland produces a lot of thunder eggs and your sample could fit.

 

[Mungoman]

Siliceous rock created a long time ago when something organic fell into a dying ocean. The water was super saturated with silica, the organic material rotted away leaving a cavity which was filled with super saturated water - over time, water evaporated away leaving silica and trace metals in the cavity, which became the rock you found.