To everyone regarding color there is a great book by Judith Forbis called
"The Classic Arabian Horse". Here is something on color from chapter 5
"Daughters of the Wind" "As to the color grey, Tesio remarks that "grey
is not itself a coat, but a pathological discoloration of the only two basic
coats which are the bay and the chestnut." Grey horses lose the pigment in
their coats at an early age, either partially or completely. As we know,
all grey foals are born either bay or chestnut (with occasional rare
exception); thus grey are of two distinct varieties, having white hairs on a
bay background or white hairs on a chestnut background. According to
Badjirmi, the Arabs divided the grey, al ashab, into seven subtypes. The
most favored was al ashab al marshoush, "and he resembles the bird and is the
strongest and tallest, and he is called al thobabi (fleabitten, also
debbani".) He also mentions in this section about al ashab al qortasi:'
"he is the one whose white is so intense so it is not mixed with any other
colour. And he resembels the white of al ghora (the star on a horse's
forehead), because it is the most intense the clearest white. And his skin
is white (pale pink). And he may have blue eyes or one blue eye. And if
his eyes are black he is called ashab akhal. Other division of grey are al
asfar, having secen sections, and al akhdar, having five: a total of 19 for
grey. All these greys have dark skin, except the one mentioned above, who
apparently belongs to the true white coat." 3 other quotes from this book
are: "If you hear that a bay horse fell from the highest mountain and was
safe, then believe it." "Behold a white horse...this is the mount of
kings..." "If thou has a dark chestnut, conduct him to the combat, and if
thou hast only a sorry chestnut, conduct him all the same to combat. The good
fortune of horses is in thier chestnut coloring, and the best (swiftest) of
all horses is the chestnut horse".