This is some of my work with gold colloids. I start with a very dilute gold chloride solution. There is virtually no coloration to this solution (no yellow tint). Dilute solutions are important for making ultra small gold nanoparticles (i.e. the red phase).

I have a special method that breaks gold clusters in gold chloride solutions down to a minimum. This allows for the smallest of nanoparticles to be produced (gold in HAuCl4/AuCl3 is actually exists in clusters). This process is carried out a number of times. The colors are more pronounced each time, and an interesting property I noted is the increasing ease of these dispersions to tend towards super boiling.

The reduction & stabilization solution is a close guarded secret, but it is well within the range of the alchemists, and uses all natural materials. During the reduction phase the colors change rather vividly: yellow, green, clear, orange, red. The clear phase was rather interesting, and I was able to take a picture of this phase (this phase is rather short) once during a small trial test. The red colloid was quite stable, but over 2-3 months degradation did occur (dulling to brown from red).

The purple colloid was made using a water extract from a special flower. The extract was quite concentrated, and only a few drops were added. The purple colloid appeared to be very stable, but no long term observations were made. The color was very striking, and the liquid appeared to be very clear.