The Dark Jewelry Star Bracelet was a dark and alternate version of the Sailor Senshi's Jewelry Star Bracelets and it first appeared in the episode "Act 21 - What Did You Do to Ami?" of live-action TV show Pretty Guardian Sailor Moon (PGSM).
It was used by a brainwashed Ami Mizuno/"Akumi" in order to transform into Dark Mercury. She would transform by saying "Dark Power, Make Up!". In the end, it was destroyed and Dark Mercury was no more.
It was really different from the other Bracelets, because the heart part and the round ones were blue and in the other ones it was pink and the heart was red and the outer side was white.