Sailor Venus' Chain appeared in different forms in the various versions of the series.
In the manga, it was a gold and ruby link chain that Sailor Venus sometimes wore as a belt, and also used for several of her attacks. The links of the chain would become heart-shaped when she performed Venus Love-Me Chain, but they were always round when she used Venus Wink Chain Sword. When she powered up to Super Sailor Venus the chain was replaced by her Love Whip.
In the anime, Venus's chain was not a physical weapon, but instead appeared as a glowing spiral of energy which she summoned to perform her Venus Love-Me Chain attack.
In the live-action series, the chain was in the same style as in the manga. Venus wore it as a belt, as did her counterpart in the reprint Sailor Moon manga. She used it to perform Venus Love-Me Chain, and also as a defensive and offensive physical weapon. The chain was strong enough to block edged weapons without breaking.