Is My SN still good?

[DuelAxle]

Hello,
I'm a little worried about the SN I bought almost three years ago being still good. Its never been opened and still in its sealed bag, and not clumping or yellow.
Its the popular brand 99.6 pure stuff from the jungle.
Any opinions out there?
Thanks
DA

 

[jodes2]

It's fine for decades if unopened. We only need 95% purity which leaves plenty for small proportion that will spoil

 

[DuelAxle]

Jodes2, Thanks for the reply. That's reassuring.
DA