Type of hook to use for this kind of yarn

[mdkb904]

I’m trying to make a ruffle scarf with this kind of yarn don’t know what kind of yarn it is or what kind of hook I should use

[Granny Square]

Do you mean a scarf like this?  https://www.lionbrand.com/crochet-pattern-potato-chip-scarf-1.html

You have to sign up to download the pattern.  This uses a yarn that looks like it might be the same weight as your yarn, but your yarn might be the next weight class smaller.

Yarn specifics from the pattern: "Vanna's Choice® (Article #860) is a 4-ply worsted-weight 100% acrylic yarn. • Solids in 3.5 oz/100g (170 yd/156 m) balls • Prints in 3 oz/85 g (145 yd/133 m) balls 100% acrylic".  The pattern uses 1 ball of a solid, so up to 170 yards.

Just eyeballing your skein, you may not have quite enough yardage if this is the scarf style you were thinking of.  Ruffles use a LOT more yardage than a plain long rectangular scarf. You might have to start with a shorter chain & settle for a shorter scarf, or leave off a row for a thinner one.

You can tell what weight your yarn is, by counting the wraps per inch.  Find a ruler, and wrap the yarn gently around the ruler between the 1" and 2" mark (I go 1" in from the end, it's hard to wrap right at the very end).  Here's a very detailed chart, in the middle is a wraps per inch column.  The Vanna yarn is 4 or medium weight, also called worsted weight, in the first column.  https://en.wikipedia.org/wiki/Yarn_weight.  Worsted/medium/4 weight is 9-12 wpi.

[bgs]

I cant tell if it is the sashay yarn or something similiar.  If so this is the pattern I used.

http://www.redheart.com/free-patterns/crochet-scarf-pattern-frilly

[Granny Square]

Bgs, that's what came to mine first but the OPs yarn looked almost like a  smooth woven or braided cord.  I didn't know that sashay style of yarn was even still available.

Edit, I guess it is...http://www.redheart.com/yarn/boutique-sashay

[Ellie 13]

Looks like a chunky size (No. 5) . I use an I or J hook on those. Should make a nice ruffle scarf.

Ellie 13

[ReniC]

1 hour ago, Ellie 13 said:

Looks like a chunky size (No. 5) . I use an I or J hook on those. Should make a nice ruffle scarf.

Ellie 13

Make a swatch from each hook and see which you prefer.