Many different stones, crystals, metals and gems can be used, depending on what specifically you want to do. Below are just a few.
Agriculture - Bloodstone, Coral,
Awaken spirit - Amber
Energy - Beryl, Brass, Calcite, Garnet,
Energy, to increase psychic - Moss Agate,
Environmental healing - Aquamarine
Fertility - Emerald, Geodes, Jade, Jasper -green,
Gardens - Bloodstone,
Gardening - Agate, Bloodstone, Jade, Jet, Malachite, Moonstone,
Gardening, talisman - Moss Agate, Coral, Moonstone,
Insect bites, to guard against - Red (or Blood) Agate.
Dancing with Nature Spirits was created in 1996.
The great spirits were kind and felt they should be one with nature. They liked nature. They were peaceful spirits, much like Buddha and believed one must find peace within oneself.
Shinto sprits are called Kami which means soul or spirit in Japanese!
There is no specific reason for it, it is just an occurrence of nature.
kami
Nymphs.
It is hard to answer, because usually all religions are based on spirits.
I think it is nature
Salt (NaCl) is an inorganic compound that is found in nature as solid crystals.
There are really crystals. That is the nature.
spirits in nature
It really depends on which interpretation you are looking at. Some people believe that Plato and Socrates felt that everything as small as hair had a form. We learn this from Parmenidies. But other's believe that Socrates and Plato did not believe in any spirits or souls at all.