If diamonds are your best friend, then you’re sure to go gaga for the jewelry, gems, minerals and fossils for sale at the expo. Watch live demonstrations as your kids mine for gemstones. $5, Saturday, 10 a.m.-6 p.m., Sunday, 10 a.m.-5 p.m., Howard County Fairgrounds, 2210 Fairgrounds Road, West Friendship. 410-832-5906. gemcuttersguild.com.