I would like to share with you the result of my 179 days long experiment. I made a copper sulfate crystal, which is over 10 cm long. Total 1.5 kg of copper sulfate was used.
This experiment is really easy and you can create it at home - feel free to check my tutorial:https://www.youtube.com/watch?v=Ik5HRyJH83s
You will need copper sulfate, hot water, and mainly lots of time...
In case you have any question about the process, feel free to contact me!