Melzer's reagent can be used to test whether spores are amyloid, nonamyloid, or dextrinoid.
* Spores that stain bluish-gray to bluish-black are amyloid
* Spores that stain brown to reddish-brown are dextrinoid
This test is normally performed on white spored mushrooms.  If the spores are not light colored, a change will not be readily apparent.  It is easiest to see the color change under a microscope, but it is possible to see it with the naked eye with a good spore print.