Main Photo Credit: http://huuphuocod2005.forumvi.com/t37-topic
Charcoals arrived at various herds throughout America during the 1960's and 1970's, and generally were named after the owner of the ranch. There are several different strains of the Charcoal gene, although some are likely the same as others, but the distinct recessive Charcoal Mutation in the UK is the Brouke Charcoal, first born on the ranch of Betty Brouke, from California, in the early 1960's.
The Homozygous Recessive Charcoal (two charcoal genes) is a grey-charcoal colouration all over it's body and belly-fur, producing the 'wrap-around' Charcoal colouration over the animals grotzen (strip of fur in the back), hips, shoulders and also belly strip. Where only one Charcoal gene is present in an animal, making it Heterozygous Recessive Charcoal, NO discolouration or Charcoal colouration is seen on the animal.
A Standard carrying Charcoal looks like a Standard, and has a WHITE belly strip.
Genetics of the Charcoal
The Charcoal is a simple recessive Mutation, similar to the Sapphire and Violet, which only shows itself fully in the Homozygous state. A Heterozygous Charcoal, or a 'Charcoal Carrier' will resemble whatever the 'base' colouration the animal is which carries the single Charcoal gene. If this was a Standard, the chinchilla would look like a Standard, etc