magic rock candy

What are the best ways to get it. Trading with prismatic shards, or haunted skulls in the quarry mine with burglar ring (0.13% chance without the ring). Please help me I need that inferior rock candy that gives +5 luck.

According to the wiki, I should be able to put the magic rock candy into the sewing machine to make a magic sprinkle shirt, but when I open the sewing machine menu the rock candy is greyed out like it isn't an option to use. I found this reddit post from 5 months ago where someone had the same...