Crewel yarn is a 2-ply yarn, usually wool, that is chiefly used for crewel embroidery, from which it gets its name, and needlepoint. Recommended by some for Persian rug repair, it is finer than Persian yarn and thicker than pearl cotton. Crewel embroidery and needlepoint with crewel yarn are used for pillows and chair seats, for curtains and wall hangings, and for ornamenting clothing and other items.
In crewel embroidery, a design is transferred to a base fabric, and then worked with crewel yarn using suggested stitches from the crewel embroidery repertoire. There is another important use of the word crewel that you should know: there is a stitch called the crewel stitch, also known as the stem stitch and the South Kensington stitch. It is used, as the second name suggests, for making flower stems, but also for outlining. However, it is only one of many stitches used in crewel embroidery.
The precise origins of crewel embroidery, and embroidery in general, are not known, but embroidery with wool has left its traces for hundreds of years, notably in the Bayeaux Tapestry. It is claimed variously that there are only 7 or 8 colors in the Bayeaux Tapestry; that it employs only crewel yarn of black, brick red, brown, light blue, green, grey and ochre – some say two shades of blue. However, there are a host of colors available today, including plant-dyed crewel yarn, very similar to the original and used by the embroiderer who – at the end of the twentieth century – made a finale to represent a possible idea of the last few feet of the Bayeaux Tapestry that were torn off and lost.
Crewel yarn is sold in small skeins of 28 yards (~26 m), larger skeins of 4 oz./750 yd. (~113 gm/~686 m), hanks of 1 oz./180 yd. (~28 gm/~165 m), and cones that are 1 lb/3,000 yd. (.45 kg/2743 m). Crewel yarn is also often sold as part of an embroidery kit that includes fabric with a printed design, a needle, instructions, and all the crewel yarn and other fibers needed to complete the project.