Canreef Aquatics Bulletin Board - blue,purple, mixed color tipped acro

my friend who came over today was looking at my tank pointed out a spiky acro that i had mounted on a scrubbing magnet told me this multicolortipped acro should not have exist in nature and is most likely an abnormality. the piece was brought from a canreef member who if i recall has his colony growing in this particular format. well this frag has blossomed magnificently in my tank with blue, purple, mixed color axial polyp tips sprouting all along its branches. is this acro a rarity or should it even exist at all? sorry lacking camera to take photo.