This is one of my favourites. I used Avon's Mosaic Effects. It came only in black (but the white just came available-I can't wait to try it!) and it's fairly easy to use. Just paint on your base colour; something bright is best and then when the first coat is dry, apply a thin layer of Mosaic and it crackles right away! It does tend to get goopy in the bottle if you don't tighten the cap really tight.
As you can tell, this was right before Christmas. The colours you can choose can be less intense, but remember to put the darker colour on second. I applied a full base coat in green and then when it was completely dry, I applied some Scotch tape diagonally across the nail and applied a generous coat of red. Once that was dry enough for handling, I peeled the tape and applied a top coat.
Firstly, I have to say that I love this pink. But the jewels are just as fun. I got them from Avon and they are slightly sticky on the back. You have to have everything prepared and ready for this one because you have to apply the jewels to wet nail enamel. Choose your colour and the nails you wish to apply the glitter to. Paint on your coat (if using two coats, apply jewels to second one) and, using tweezers, place on diamonds while still wet. Then, apply colour to other nails. Once everything is thoroughly dry, apply a top coat. These jewels stay on pretty good but I only use them when I'm going out as wear and tear of the day can wear them off. I found some great stickers for nails at the Dollar Store (go figure) that don't come off until you remove them and look awesome.