At my talks I have mentioned dowsing rods and even given demonstrations using them. If you are going to become an Earth Healer, or wish to learn geomancy you will need to buy a pair of dowsing rods, or L-Rods. They are called L-Rods because they are in the shape of an "L."
Pendulums will not cut it. You need L-rods because they can guide you to locations, or aspects of Mother Earth by pointing in a specific direction; and when you get to the location of your query they will indicate that you have arrived by opening up (or crossing, or swinging.) This is invaluable. Imagine how many questions you would have to ask with a pendulum to find a location of something like a Ley Line. Secondly, they can trace a formation of Mother Earth such as an Earth Chakra, or show you the directional angle of a Ley Line. For example, an accomplished Geomancer can hold an L-Rod in one hand over the intersection of several Ley Lines and have it rotate slowly and stop each time it gets to a Ley Line, thereby showing you its direction. They can also indicate the directional flow of an energy line.
Most importantly once you get good at using L-Rods you will develop a bond with them and they will begin to alert you things. For example, I may be looking for a Ley Line and my rods will suddenly point in another direction, alerting me to something that might be of interest to me. Or they begin to move in a very distinct pattern notifying me that something particular is there. This might be something as simple as spinning around to tell me--"Hey There's A Vortex There." These are all movements unique to me and my rods that we have developed over the years. Call it something additional to a sixth sense, or your intuitive sense.
L-Rods can perform all the functions of a pendulum such as answering your questions. YES--they open up; NO.-- they cross. If you are interested in using them like a pendulum I suggest buying an expensive sensitive pair that will move freely in its sleeve and be sensitive to the slightest movement.
If you can afford it, I would buy two sets of L-Rods and keep one set in your car for when you run into things, or misplace your other pair. When I first started to dowse I was constantly searching for Ley Lines, or what I call Spirit Lines. Wherever I went I would search for them. If you want to become a good geomancer you need to dedicate yourself, at least initially, to developing your craft. MAKE IT YOUR FOCUS!!!!!!!!!!!!!
I would not let anyone else use your dowsing rods. I used to think it was okay to let others use my rods, but came to realize a bit of whomever touches your rods, stays on your rods. So treat them like your toothbrush.
When buying L-rods make sure that they have a sleeve around the portion you hold in your hands so that they can spin about freely. L-Rods look like a Right Angle (what carpenters call a framing square) when you hold the shorter part in your hands. Also make sure that the wire is not too flimsy or light, because they will bend. When they become misshaped they loose their balance. Although some folks have told me they like the light ones and don't mind that they get bent. Conversely super thick ones will be heavy to hold for long periods. You want something that will respond to your intention. Ultimately, if you become a good geomancer it won't matter as much; but it is always nice to have a sensitive pair of rods.
The Key is to buy one with a sleeve so it moves easily. The ability for such movement is critical for geomancy techniques such as finding vortex, or gauging Imprints (Land Imprints/Memories, Geographic Samskaras.)
Where to Buy L-Rods
The American Society of Dowsers has plenty to choose from: ASD Bookstore
Fisher Creek has a selection of higher end more expensive http://www.dowsingsite.com
(Note since post appeared Fisher Creek is no longer selling L-rods.)
Both Amazon and Ebay list sellers of L-Rods.
You may also wish to check a metaphysical store or Psychic Fair for rods.