Formality of Cloth

[Guest]

How would you rank the formality/dressiness of various cloth?

Something along these lines, from most formal to least?:

worsted wool
silk
flannel
tweed
linen/cotton

[Guest]

All things being equal, that's not a bad ranking. But other factors play a role: color, pattern, and styling. As a practical matter, it's hard to say in every case which is more formal than the other. Is navy linen more or less formal than cream doeskin? Worsted tween 3-piece more or less than an unlined, patch-pocked fresco? We enter angles-on-the-head-of-a-pin territory before too long.