Google maps will only get you to the general area. Take the marked corner off from highway 50 west out of Ely. Then go about two miles (going past the Google maps destination) and turn right at the BLM sign indicating Garnet hill ( but no arrow pointing right). It doesn't take long until you're climbing a fairly steep dirt road (Subaru Forester had no issues). Near the top you have to turn right again and keep going up. Not too far from this turn that feels like the end of the trail you get to a parking area and scenic overlook.
Definitely off the beaten path, but worth it. We enjoyed digging about using sticks and pointed rocks and did succeed in finding several small garnets.