Alexandrite Light Detecting Lantern

Alexandrite is a real gem that changes colour depending on the light shining on it. What if we could craft that rare gem into a special lantern that would change colour depending on the light level that you're standing (as you hold it), or the block which it's placed on. This would mean that players could hold this lantern in their off-hand while placing torches with their main-hand. This special lantern wouldn't give off any light itself, but would appear to have a slight glow to it.