Okay, let me tell you about my weekend experiment with this black iron oxide powder. I bought it specifically to make magnetic slime after reading that one hilarious review about turning kids into Venom.
First impression? This stuff is DARK. Like, 'accidentally-spill-it-and-your-kitchen-looks-like-a-crime-scene' dark. The plastic jar is sturdy though - no spills during shipping unlike some poor reviewers experienced.
Mixing it into slime was... an experience. Pro tip: WEAR GLOVES unless you want to explain black-stained hands at work on Monday. When you add it to liquid slime mixture (about 2 tablespoons per batch), it creates this incredible tar-like substance that actually moves toward magnets in real time - way cooler than my old silly putty ever was.
The color payoff is intense - one batch turned my white mixing bowl permanently gray. But watching my nephew's face when the black goo started crawling toward a magnet? Priceless. His mom did indeed ask if he'd been possessed by an alien symbiote.
Bonus discovery: It works great for coloring other projects too. I tested a small amount in some clay and got a nice dark gray after firing (though it does lean slightly brownish). The pigment mixes smoothly into water-based mediums, but good luck cleaning up afterwards - this stuff stains everything.
For the price and quantity, this is fantastic for crafters who don't mind getting a little messy. Just... maybe do your mixing outside.