".Oxford online dictionary mentions that it was a trademark and also specifies
This hypothesis is consistent with the name of Alcian green, which is a tetraphenyl-phthalocyanine with copper.However Prof. J. E. Scott who had cracked the Chemistry of Alcian blue himself and later received confirmation from the manufacturer (ICI) wrote that Alcian was a trademark that ICI preferred to be spelt starting with a capital "A", and he presumes it came from the old English word "halcyon", which has a "romantic and poetic associations with the kingfisher bird and calm seas".