Editing Crochet hook (section)

==Construction==
Crochet appeared as a distinct [[textile arts|textile art]] during the early 19th century, and many crochet hooks survive from that period. These can be sorted into two groups, the one with thin steel hooks that are set into separate handles, and the other including single-piece hooks made in a variety of materials. The distinction between steel and other hooks persists to the present day, although all are now commonly of single-piece construction. A variety of coverings may be applied to the handle for ergonomic reasons. Ornate handles have also been added throughout time, with one method being [[scrimshaw]] during 19th century Europe.<ref>{{Cite web |title=Scrimshaw crochet hook |url=https://collections.sea.museum/en/objects/21460/scrimshaw-crochet-hook |access-date=2024-04-25 |website=collections.sea.museum |language=en}}</ref>

Crochet hooks are currently produced in diameters ranging from 0.35&nbsp;mm to 25&nbsp;mm. These diameters are indicated both directly in millimeters and by various numerical or literal [[List of United States standard crochet hook and knitting needle sizes|gauge systems]]. Hooks under 2.0&nbsp;mm are made of steel (for its strength) and are alternately termed steel-, lace- or thread hooks. Hooks of 2.00&nbsp;mm or larger diameter are called yarn hooks or regular hooks. Aluminum is the predominant material from 2.0&nbsp;mm to 6.0&nbsp;mm (for its lighter weight). Beyond that, bamboo, wood, and plastic are the more common materials (for their even lighter weight). The indicated size boundaries between the types are, however, approximate. With the exception of the thinnest hooks, which are invariably made of steel, other materials may be encountered outside the indicated ranges.

Historical materials for handles and some one-piece hooks include bone, porcupine quill, celluloid, agate, ivory, and fossilized mammoth ivory.<ref>[[Donna Kooler]], ''Donna Kooler's Encyclopedia of Crochet'', Leisure Arts, Inc., Little Rock, Arkansas, 2011, p. 13.</ref>

Longer hooks are used for [[Tunisian crochet]] to accommodate the lengthy rows of open loops characterizing that style. A form with hooks at both ends is also used for Tunisian and other types of crochet that cannot be made with the standard hook, such as [[cro-hook]]ing.{{citation needed|date=March 2023}}