Can Anyone Identify These Rocks

[julia298]

Can anyone help with identifying these rocks?
Ive put in a pic of the rock followed by a close up of each one, in case theres any geologists, or budding geologists out there.

I apologise in advance if these pics are rubbish.

1.

2.

3.

4.

Thanks for looking

 

[a.d.wood]

Hi there,

Granite (deifinately 1,2 and 4. I think 3 as well but a good few years have passed since I studied geology), if they're clean then fairly harmless for your tank (won't effect the pH or hardness like limestone would).

Andrew

 

[julia298]

Thanks for your reply Andrew.

Al have been jet washed & roasted in the oven, just waiting for information on what they were to decide if safe for aquarium.

 

[SirMinion]

A few drops of vinegar on the stones will tell you if they're too alkaline to put in your tank. If they don't fizz, then they're fine.