I Love Rainbows. I found a good deal on Ebay for Feng Shui Crystal Balls...they really do sparkle and cast many rainbows all very my room from my window. I got the 40mm but I think the 30mm would of been better, because the tiny sides would of been at more angles, sometimes bigger isn't always better. I have a 20mm  Swarovski crystal, and it does seem to sparkle more actually, due to size and I think a higher lead content) but not complaining, I got a great deal and my room is very festive on a sunny day. so if you like sparkles in a sunny window, get a 20-30mm crystal faucetted ball. do not however, hang one on your car's rear view mirror! I came to a quick stop once, it swung into my windshield nearly cracking it.. LOL not a good idea, stick to house windows, and not to where a breeze can cause these heavy boogers to swing into the glass!