Is there any way a diamond necklace can be fake?

Michele asked: First of all, here’s a link:
http://diamonds.ross-simons.com/rs/show_product.jsp;jsessionid=01085DF0661389E6AD009572EEC3CCB6?Prod_ID=223348&qid=RSDB-S03_i01-071001-16:35:36-49655
I found this online and I’m totally in love with it. I just hopes it looks as good in real life!
Anyways, is there any way diamond necklaces can be fake, kind of like designer purses can be?
I really want this necklace, I’m just paranoid because I would have [...]

what all to take care when buying a diamond ring or a diamond necklace?

gaurav r asked: diamonds features like cuts , clarity etc