@ eptheta. Beautiful crystals, I don't know how to grow only one. My formal education stopped at the 9th grade so I'm a self taught scientist. I prepared a supersaturated solution of cane sugar and carbon filtered tap water in a quart mason jar with a piece of cotton Venetian Blinds cord...
Here is a pic of a cane sugar crystal cluster I grew in about 9-10 months. I changed the solution and container several times. I donated it to the local High School Science Teacher, the kids probably ate it. :)