Jewel Chao
Alright how to:
You don't NEED a Sonic Advanced Game to get jewel chao. I've never had them. You can get a short-term garden by hooking up your Gameboy to your Gamecube/Wii, then putting your chao into the adapter available in every garden. Now, using the Gameboy, you'll have to do the mini games available in the Tiny Chao Garden. Unfortunately it takes a long time to get the thousands of rings that are required to buy a jewel egg. But one you buy one, just put it back into your Gamecube/Wii chao garden.
List of all jewel chao and their prices:
Silver Chao - 500 Rings
Gold Chao - 1000 Rings
Ruby Chao - 5000 Rings
Sapphire Chao - 7000 Rings
Amethyst Chao - 8000 Rings
Emerald Chao - 10000 Rings
Garnet Chao - 12000 Rings
Aquamrine Chao - 14000 Rings
Peridot Chao - 16000 Rings
Onyx Chao - 20000 Rings
If you don't want to buy the gold or silver chao, they are found as eggs from the Sonic DX: Director's Cut game. The Silver is available by pushing a stone in the base of the lake in Mystic Ruins, resulting in you watching it plop from above and slowly float to land. After you see the gold egg in a store in the city, look to replace the door weight with a statue or rock...(i can't remember) found where the back street ends. Um, yeah lol.