I am pretty sure the Haworthia Variegation is real.
But the Astrophytum Asterias variegation is fake. A plant with no prior variegation cannot turn variegated without some kind of treatment. The Japanese have classified variegation into 2 types. Hake-han and hade-han. Hade-han is an unstable form of variegation. The yellow and green is not evenly distributed. Hake-han is a stable form of variegation. The yellow and green is evenly distributed. The astrophytum shown above is neither form of variegation.
There is also "khoyo" colors on certain astro species mostly myriostigma.
Here are some pictures pulled off the web. First 2 are from Frank Kamei.
Hade-han variegation:
Hake- han Variegation:
Fake variegation:
Khoyo colors: (Photos by frank kamei)
Fake variegation:
