Are sparring gloves (mma) meant to be soft or hard?

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I recently acquired a pair of Everlast MMA gloves for sparring (well thats what it says on the package) and the "padding" is pretty hard, feels like an over-inflated tyre or something. But i tried it out a few times, hit a friend once and actually bruised him :S

I usually dont train with gloves, so im a bit new to this glove thing. So...are they meant to just protect the fighter's own hands, or are they meant to be soft to avoid injuring the opponent?

thanks