See bottom of post for update.
I know that Van Cleef & Arpels' iconic clover necklace will cost you quite a bit, although I was unable to find an exact price online. Below is a photo of Reese Witherspoon wearing the onyx version (photo credit). (Click here to see Reese in the mother of pearl version.)
If you love the style of the original but are looking for a more budget friendly version, check out NY Light Metal's Etsy shop. Here's what the owner Regina had to say about her stunning (and affordable) clover necklace..."It's my own take on the timeless clover leaf necklace, which is gorgeous, but oh so financially devastating! This one is totally affordable and relates the same fresh, flirty design of the Van Cleef & Arpels version."
If you'd like to purchase from Regina, this necklace retails for $45 and you can click here to purchase (I highly recommend it - I ordered the black/gold version over the summer and wear it constantly!!). Also available in turquoise, yellow, red, or mother of pearl. Also be sure to check out ReginaPierallini.com to check out her higher end line of one of a kind jewelry.
*Update - 3/12/10* - Regina just emailed me the newest version of this necklace from her spring collection and I am in LOVE! It is made up of beautiful mother of pearl clovers framed in 14k gold...seriously stunning. If you're as in love with it as I am, it retails for $85 and you can click here to purchase (tell her The Look 4 Less sent you!).
*Update - 4/11/11* - I am still the biggest fan of Regina's jewelry as an alternative to Van Cleef & Arpels but a reader sent me this find and I wanted to share. Target has a 5 leaf daisy enamel necklace and earring set which retails for $33.99 on sale. Click here to view/purchase.