Details In Raw - concrete test failed

So poor me this time, test has been failed, I found that the concrete is not capable for too many different kinds of chemical.

Details In Raw - Pen holder

The first test sample is finally done, I quite like using cement to create some art pieces or products, even though it's such a raw medium. I guess it can be made to be a more fine object, keep trying. But it's quite trouble to buy the professional pigment in Hong Kong, if anyone knows please tell me, many thanks!