Cinder

[Sumair]

Hi,guys I'm a newbie,I live in India,Bangalore and in Bangalore people sells cinder(lava rock) locally 20kg for $4 but I'm stuck to buy it bcz I'm confused it is inert or not so do I buy it

[George]

Lava rock is used a lot in Hawaii.

A vinegar fizz test will show with certainty whether it should be used.  Search vinegar on this site.

[Sumair]

Thank u George yeah I watched videos on YouTube and my cinder is not bubbling