chrome alum

I am trying to make potassium chrominum sulfate, aka, chrome alum.

I begin with 5g of potassium dichromate and dissolved it in a minimum amount of water. Next I add 15g of battery grade sulfuric acid, adding in small portions and stirring while keeping the temperature below 50C. The temp is kept below 50C by an ice bath. After all the sulfuric acid is added, I add 25g of denatured alcohol. What I get is a purplish solution which over time turns greenish. I put it into the fridge and several hours later, I have crystals at the bottom. But its more like a sludge rather than crystals. I'm not sure what I'm doing wrong but I can't seem to get the dark violet crystals.

Has anyone tried this experiment and successfully synthesize potassium chrominum sulfate crystals?


[Edited on 7-2-2012 by jamit]