The 4 Elements

[Jewel-ry]

Earth - bloodstone
Fire - carnelian
Air - Amethyst
Water - moonstone

I also liked lunas idea of pyrite for Earth, because its so natural and so beautiful. Good idea luna!

j

 

[Siwan]

I would use:

Water - Rose Quartz
Air - Amethyst
Earth - Onyx
Fire - Amber

 

[Pollux]

It would actually depend on the purpose - whether it be a ritual, a spell and so on...
I generally use Purple, Orange, Dark Blue and Black for Air, Fire, Water and Earth Candles.
My choice of stones would most probably be: Amethyst, Carnelian, Aquamarine, Labradorite.
In Spring/Summer times, I go with Azure, Red, Green and Black, so my picks would be Fluorite, Diasper, Jade, Salt.

 

[Shade]

I have a set of four stone I use to represent the elements in meditation and when I do outdoor rituals and don't want to use candles.

Air - Mottled Jasper

Fire - Carnelain

Water - Beryl

Earth - Malachite

I chose these stones based on their place in the elemental tables in Cunningham's book and their color. So far they've worked well.