Font Awesome in fields

Hello,

is it possible to add some font-awesome code in the fields as a placeholder?
Here is my page: http://juwelierrubingbr.alfahosting.org/meinrubin-neuer-shop/produkt/2-x-333-echt-gold-trauringe-rotgold-weissgold-rosegold-eheringe/

As you can see I tried to add some HTML-code in the field, but it is not accepted.

Can you help me?

Thank you very much!

https://ww.wp.xz.cn/plugins/wc-fields-factory/