Hammer corals are widely available in many colors and many prices, I mainly look at the contrast between the base and tip to decide which I like most. If it’s dull purple on dull green you shouldn’t buy it if you have limited space for corals. Keep looking around and sooner or later you’ll find a combination which you love on first sight. If you like the purple and contrast buy the frag and watch it grow over the years.
If you want to compare you can search google for pictures of other purple tipped euphyllias.
(Also there is a difference in hammer corals, you have ancora and paraancora. The first one grows slower, is more difficult to propagate and commands a higher price)