ROPPYAR Magic Ball Sculpture Toys with 222 Pcs and 5mm for Intelligence Development and Stress Relief or Decoration (Rainbow)

I was hesitant to buy this version in black. I have bought several sets of variously colored 5mm magnets and they tend to get dull over time (gold becomes diaper-brown). I don't know for sure, but I'm pretty sure these are powder-coated, not plated, because they are EXCEPTIONALLY color-fast. They also have a slightly more tactile feel. I have bought MANY sets of these that I intersperse with my colored magnets to form somewhat elaborate patterns with a dark black matte background. If they are actually powder-coated then they will last FOREVER. But, so far, they have held up to months of heavy use without the slightest loss of their deep black matte finish. I have CHROME magnets that have not held their "color" as well as these. I am amazed at the quality.