Rabicano is a white-added color pattern that shows up first in white hairs at the top of the tail of a horse color that normally would not have them.  From there usually some degree of roaning, that is, white hairs mixed in with the colored ones in a salt-and-pepper effect, results, mostly on the horse's barrel.  Often they form a striping effect, as though the ribs were being defined in white stippling.

Here is one striking example of Rabicano, on a black Arabian stallion, Aswad Shahwan.

Click thumbnail photos to see full size.

Amir Seralim BWA x Sirenas Ellen BWA
Aswad Shahwan is a Black Rabicano 
Straight Egyptian, Sheykh Obeyd, Asil, Al Khamsa and Blue List Eligible Stallion.

Under his belly, his skin is mottled black and pink 

He not only has roaning but he has marbling between his front legs and down the center of his belly and out to his gaskins and the skin under the marbling is mottled. It is pink with black dots the size of an eraser head on a pencil. Also he has bright pink spots between his back legs. Two are the shape of a bowtie and one is round and smooth edged. He has detached white markings on his legs as well. Anyone who wants to see more photos can go to http://www.zohararabians.com/index2.htm