The web site below (despite its smart aleck tone) has a lot of good suggestions for growing crystals.

So, in order for crystals to start forming, there has to be a nucleation site.

They found a similar age for crystals of the mineral pyrite near the gold.

Nundle is noted as one of the best areas in the State for crystals.

For crystals the electronic band structure determines the density of states.

The vesicles then rupture and act as a centre for crystals to grow on.

You cannot just walk up to them and ask for crystals.

Several scientific experiments will be conducted on the flight, including one testing a process for growing crystals in space.

Keep in mind that, for bigger crystals the color doesn't need to be very concentrated to look strong enough.

Sometimes pressure needs to be applied to a substance for crystals of it to form.