T-Shirt Ghetto

I need to wear a scarf over my evening gown but don't know what material matches my gown which is a black dress in a soft material (not as soft as silk but not so rough either). One scarf is made out of thin see through polyester that kind of feels like pantyhose (not the silky sheer kind). It's a regular black. The other is a shimmery black thats a shiny and sparkly material whereas the dress material is not shiny, but it looks fancier than the other

So which do I choose? One is a little too casual but the other too flashy and shiny. Neither are an exact match to the dress material. It is for a black tie event. The sales clerk recommended the plain one until she saw the designer brand and expensive price of the shiny one so I can't tell if she suddenly liked the fancy one because it matched better or if she wanted to ring a bigger sale charge. What do you think?