Rachael Leigh Cook is wearing at least two necklaces here, a longer pendant necklace in yellow gold and two shorter (or one multi-strand) gemstone necklace with alternating beads.
I found a two-color 14K gold filigree pendant that's a close match (Buy Direct).
Here's a link that lets you browse a selection of filigree pendants. (Compare Prices)
Be sure to look at Anna Chlumsky's pendant earrings if you like filigree jewelry.
Step Up Women's Network is a non-profit organization that works to strengthen community resources for women and girls.