How to tell whether factory(?) brake pads are organic or metallic?

[proletariandan]

Changing rear pads on my Stigmata - there is an 'O' on the back of the pad below the series of numbers. Does that mean it is organic?

Thanks!
Dan

[tony_mm]

Shimano, SRAM, ..??

[Mark McM]

If they squeal like a banshee any time you brake, they're metallic ...

If they are completely worn out after two wet and muddy rides, they're organic ...