Anything can be used to dowse with. It does not have to be a crystal pendulum or a wooden pendulum. A washer on a string will work. However most people have a favourite crystal or wooden pendulum made specifically for dowsing.
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To begin to dowse be as present and focused as possible. The best answers from dowsing pendulums are achieved when the outcome is not vital and personal involvement is not over emotional. Try to be in a calm balanced space. Hold the pendulum chain or chord between the thumb and first finger and give it a gentle swing backwards and forwards. The first questions will be to find out which way the pendulum swings for a yes and which way it swings for a no. Ask the pendulum questions you already know the answer to. For example you could ask the question "am I male" or "am I female". Once you have determined which way it swings you can begin with simple questions. Some people find it helpful to make a chart from a circle or half circle and divide it into sections. This can be used to find out which Bach Flower Remedy or vitamins to take or what the best way forward would be out of a number of choices.