There were a few varieties. The Ketchum grenade was thrown or lobbed and had a fuse on the tip. There were also Rains grenades, basically the Confederates took the idea of the contact fuse on a Ketchum grenade and buried it nose end up in what amounts to the first landmines. The Union hated these and there's stories of them marching POWs at the head of their columns.

https://armyhistory.org/mine-warfare-in-the-civil-war/