Amber is fossilized resin or tree sap. It is an organic gem, and not really a crystal at all.
When I performed guided visualization after my introduction to the runes, I had a vision that the goddess Freya gave me a piece of amber marked with the rune Perthro in gold.
This fossilized tree resin is the stone of healing and pain management. Placing amber on areas of the body can draw out disease, pain, and cleanse the mind, body, and spirit. It can also cleanse the local environment, thereby removing negative energy. It has been used traditionally for protecting children, but also serves as an effective teething piece, and represents unconditional love.