What types / Shapes of Pendulums?
Depending what are they used for, they can be for healing specific illnesses, for adjusting chakras, tele-radiesthesia (distance healing, map dowsing).
Types of Pendulum
In its simplest form, a Dowsing Pendulum is nothing more than a weighted object at the end of some type of string or chain that weighs less than the weighted object. This creates a situation where the pendulum is capable of swinging freely when someone holds the chain and allows the Dowsing Pendulum free range of motion.
Most pendulums you purchase are made of some sort of metal chain or heavy cording. The "bob" aka "pendulum bob" can be made of virtually anything as long as it is heavy enough to keep the chain or cording taunt while using it.
Some of the more commonly used materials for the bob are crystals, metals or other gemstones. Often they have been shaped to specifically come to a point on the bottom with a reasonably flat surface at the top to connect the chain to. It is not unusual however for a tumbled gem stone of a freeform shape to be used with a bail attached to one end.
Some people that make pendulums bestow various powers upon the pendulums they make. Practioner of Witchcraft and Wicca tend to be some of the groups that do this. Other groups that do this include practioner of Reiki and those with other magical affiliations.
Dowsing Pendulums can be cleansed of negativity, empowered to focus on specific items or types of items such as a Pendulum keyed to dealing with financial matters, health concerns or any other specific thought or item. This is much the same as a ring, pendant or other piece of jewellery being charged with a magical power, but the purpose is more to help locate the object versus bringing the object to you.
They can also be Simple: tear drop, ball-shaped, conical, spiral, made from brass, copper, crystal, wood, ceramic.