Crochet thread is specially formulated thread

Thread (yarn)

Thread is a kind of yarn used for sewing.-Materials:Thread is made from just about everything. Following table lists common materials, a general description and what they are supposed to be good for. If your machine will sew with the thread, any thread can used for just about any purpose. This...

 usually made from mercerized cotton

Mercerized cotton

Mercerization is a treatment for cotton fabric and thread that gives fabric or yarns a lustrous appearance and strengthens them. The process is applied to cellulosic materials like cotton or hemp.-History:...

 for crafting decorative crochet

Crochet

Crochet is a process of creating fabric from yarn, thread, or other material strands using a crochet hook. The word is derived from the French word "crochet", meaning hook. Hooks can be made of materials such as metals, woods or plastic and are commercially manufactured as well as produced by...

 items such as doilies

Doily

A doily is an ornamental mat, originally the name of a fabric made by Doiley, a 17th-century London draper. Doily earlier meant "genteel, affordable woolens", evidently from the same source....

 or filet crochet

Filet crochet

Filet crochet is a type of crocheted fabric. This type of crocheted lace is gridlike because it uses only two crochet stitches: the chain stitch and the double crochet stitch Filet crochet is a type of crocheted fabric. This type of crocheted lace is gridlike because it uses only two crochet...

. Crochet thread produces fabric

Fabric

A fabric is a textile material, short for "textile fabric".Fabric may also refer to:*Fabric , the spatial and geometric configuration of elements within a rock*Fabric , a nightclub in London, England...

 of fine gauge

Gauge (knitting)

In knitting, the word gauge is used both in hand knitting and machine knitting; the latter, technical abbreviation GG, refers to "Knitting Machines" fineness size. In both cases, the term refers to the number of stitches per inch, not the size of the finished garment...

 that may be stiffened with starch

Starch

Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

.

Differences from yarn and sewing thread

Crochet thread is almost always produced from cotton and has a denser pile and smaller diameter than ordinary yarn

Yarn

Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or...

. Most crochet threads are thicker in diameter than sewing yarn. Crochet thread can withstand considerable stresses from pulls with sharp hooks.

Crochet manufacturing conventions treat thread and yarn quite differently: manufacturers designate different sizing scales for thread and yarn. Thread is generally packaged on spool

Spool

Spool can mean one of the following:*Spool, a usually low-flanged or unflanged cylinder on which thread, wire, cable, paper, film, or tape is wound for distribution or use....

s instead of skeins or hanks and is offered for sale in a separate section from ordinary yarns or threads. Crochet hooks for use with thread are also sized according to a different scale from yarn hooks. Thread hooks are also manufactured differently from yarn hooks: modern yarn hooks are usually aluminum or plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

, while thread hooks are made of steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 and have smaller hook heads and shorter shanks.

The division between yarn and thread is somewhat arbitrary: crochet thread at its thickest is similar in diameter and behavior to fine cotton yarn. The largest sizes of thread crochet hooks overlap with the smallest sizes of yarn crochet hooks.

Sizing

Crochet thread comes in sizes from 3 to 100, although historically it came in much finer sizes, down to 200. Diameter is inversely proportional to number, so size 3 is nearly as thick as yarn and size 100 is as fine as sewing

Sewing

Sewing is the craft of fastening or attaching objects using stitches made with a needle and thread. Sewing is one of the oldest of the textile arts, arising in the Paleolithic era...

thread. Thread may also be categorized by number of plies and size 10 thread is known as bedspread weight. Smaller sizes (40 and up) are rarely used anymore.