A general word about HOOKS for crochet....
ALUMINUM HOOKS are labeled with a letter and a milimeter indication. As in Lynne's hook, she wrote that it is an H/5 mm hook.
With aluminum hooks, the HIGHER the letter, the LARGER the hook. So an H or a J are much bigger hooks than a C or an E. The larger the hook, the heavier the yarn you can use it with. And the bulkier the piece will be. A big hook with a more medium weight yarn will give a loosely woven or loopy appearance.
Aluminum hooks are the ones you most commonly see used for garments, blankets, and decorative projects.
STEEL HOOKS are numbered. With steel hooks the HIGHER the number, the SMALLER the hook.
So a Steel Hook 7/1.5mm is LARGER than a Steel Hook 9/1.25mm
Steel hooks are the type used for doilies, lacy work, collars and cuffs, fancy edgings, etc.
Utilizing thread, rather than yarn, these hooks makes very delicate work indeed.
The threads for steel hook come in an assortment of thicknesses. A 10 thread is heavier than a 20 and a 20 is heavier than a 50. The finer the thread, the smaller your hook should be, generally speaking.
Merme