A carpet's basic qualities depend on its construction: whether the pile is cut, looped, or both cut and looped.

Cut-pile carpets have loops trimmed off so that yarn ends poke upward, creating a luxurious look and feel--clearly one of the reasons they represent 60% of carpets sold. Within the cut-pile family are the highly popular "saxonies." Saxony plush has densely packed, short, level tufts.

Textured plushes have slightly taller pile and are less dense. "Freize" (free-zay) carpet is a somewhat rare, rugged, nubby style with a dense, low pile and tightly twisted yarns. Another type of cut-pile carpet is the velvet, with short, very tight pile.

A velvet carpet is smooth, level, and uniform with a formal look. When you walk on it, footprints tend to show (the more textured a surface, the less it shows footprints).

A cut-pile carpet's "hand"--the look, texture, and feel--is a result of the fibers chosen for the yarn and the yarn's gauge ("denier") and twist. These elements are critical to performance. The more tightly twisted the yarn, the better the performance, as a rule, because the yarn retains its shape over time. Most cut-pile yarns are heat-set to hold their shape (the same way a hair permanent heat-sets a hairstyle).

Loop carpet, the result of tufting, has complete yarn loops that stand upright. Loops tend to wear better than cut-pile carpets because the yarn tips are not exposed. With these, yarn wears on the sides, not the ends, and the twist is automatically maintained.

For a particularly smooth surface, often preferred in commercial installations, you can get a "low-level loop." For striking patterns or a sculptured look, you can buy a "multi-level loop." Sculptured carpets have both high and low loops.

High- level loops, such as Berbers, create a nubby texture. In fact, most loop piles are now called Berbers, a term that originated with the rugs made by the nomadic Berber tribes of Africa.

Cut-loop pile and tip-sheared carpets combine loops with cut pile. The cut-loop pile has cut ends that are taller than the loops, creating a variety of looks. Conventional types, sometimes called "sculptured" carpets, offer bold patterns and colors. More subtle versions, called "traceries" or "carved saxonies" merely suggest a pattern.