To ask if anyone (who knows their chemistry) knows of a reliable home test for borax?

[Transpeaked]

Just that really - ordered borax from amazon seller and it’s arrived in a clear zip lock plastic bag and it could be anything for all I know. ID rather make sure it’s borax before mixing it with other chemicals/compounds.

Mix half a teaspoon into one glass (100ml) of warm water until dissolved. Then add a bit of the solution into PVA (white craft glue) or peel-off face mask. If it causes the glue/mask to solidify into a slime or putty-like mass then it's definitely borax.

You can also use pH test strips on the borax solution. It should up fairly strongly alkaline.

This is why I love Mumsnet!

Thank you

You can also use pH test strips on the borax solution. It should up fairly strongly alkaline
But that will just prove it's alkaline, not what chemical it is. Caustic Soda will give the same result.