As I remember from the same discussion several years ago, purple heart
is a common name for about 6 different trees. The response of the wood
may depend on the particular tree the wood came from.

You can look at a stack of purple heart and see at least a couple
different color tones in the different boards. I once made the mistake
of buying a plank then going back to get another and ended up with two
different purple hearts. The jewelry box never did look right.

I've had a plank in the garage near the door for several years. It has
kept its color. When I cut it it turned brown but within a week it was
back to a nice color again for finishing of the jewelry boxes.

220grit wrote:
Hi, I'm making some varnished rope bins for a sailboat deck out of
purple heart and mahogany.
The ph looks fabulous when I get it but after I sand out the planing
marks and mill it the purple color fades to kind of a dirty gray. What
am I doing wrong? Heat from the orbital sander? Is there a way to
restore the color? I'm kind of new to this. Thank you for your time.