To all who played HARVEST MOON MORE FRIENDS IN MINERAL TOWN in gameboy advance   

Unfortunetly, I forgot where the jewel of truth was (or what it was...)
Van is a character from Harvest Moon: Another Wonderful Life. You can activate him by connecting your GBA and Cube while both games are inserted. If you go to IGN.com, there are very helpful tutorials for H:MFoMT.

you'll find them in mines, continue digging, from a shelf in the second floor of the library, from the lamp post near the park, watering trough in the horse shed, dog house, exchange it with winnings in the horse race, forgot the others. Van is in GC's Another Life, play it the same time with friends of mineral town, communicate thru harvest goddest at the spring.