This hat is made from Corriedale and Suffolk wool, with variegated sections of gray/blue, red, and magenta in a blend of silk and Merino wool.  It covers most or all of the ears, so is a round cap.  Skull caps cover about half of the ears or less, so this is a longer hat.  The black is actually two different colors.  The wider section is a reddish black, and the rest is a blue/black.  So the two blacks pick up the two dominant colors of red and blue.