Colloidal gold, like all true metallic colloids, changes colour with changing particle size.
Yellow at 13nm Red/Orange at 15nm Red at 30nm Wine Red at 30 - 40nm Violet at 50nm Blue at 70nm For further info see the Mie Theory of light scattering and extinction. Regards Ivan. > -----Original Message----- > From: brian...@hotmail.com [mailto:brian...@hotmail.com] > Sent: Monday, 25 November 2002 2:37 p.m. > To: silver-list@eskimo.com > Subject: CS>Re: Colloidal Gold > > > I believe CG's colour should be pale purple through red and > then to deep > blue with increasing gold concentration. I don't know if > particle size would > effect the concentration. > > One method that's used to produce CG is an underwater high > voltage arc > between gold electrodes seperated by about 1/4". A neon > sign transformer > typically is used as it has the characteristic of being > effectively current > limited and able to produce enough voltage to keep the arc > sustained. > Commercial neon sign transformer are limited in the range > of 20 to 120mA, > with the most common units being 30 mA. It has been > mentioned to me that > 15Kv (15 thousand volt) neon sign transformer with 60mA > capacity is what > gives good results. These neon sign transformers have an > alternating (AC) > output. The high voltage (15Kv) would, I assume, start the > arc, and then the > neon sign transformer will adjust output voltage to some > lower voltage to > keep it's current limited output going through the arc. > Electrode spacing > apparently has some effect on current as well. In a > previous post, it was > said that keeping the gold electrodes small was required to > sustain the arc. > I believe, the arc, in effect, releases colloidal gold > particles. This > method also uses distilled water that's cooled and kept in > motion during > the process; a bit different than the process described by akaJhon. > > BTW, I've received many responses to my query about > creation of a colloidal > gold discussion grup. They are all encouraging me to setup > this list, so > I'll proceed. It's been suggested by several that > moderation is essential > for such a group for various reasons. More details to follow. > > Thanks! > Brian. -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>
