What is the X in X-mas?
animal fibre obtained from the manes and tails of horses and ranging in length from 8 inches (20 cm) to 3 feet (90 cm) and most often of black colour. It is coarse, strong, lustrous, and resilient and usually has a hollow central canal, or medulla, making it fairly low in density. Hair taken from the mane is softest and ranges from 50 to 150 microns (a micron is about 0.00004 inch) in diameter. Hair from the tail, coarser and with greater resilience, ranges from 75 to 280 microns in diameter and is marketed separately