This is a Septarian Stone aka Dragon Stone; I bought it in a local store while browsing... I saw it and thought it was very unusual and just had to have it. This stone is larger than the palm of my hand and has a good solid weight to it. I find it's appearance fascinating... from the yellowish crystals on the inside to the scale like appearance of the outside.
Septarian is a result of volcanic eruptions and dead sea life that formed into mud balls (nodules) 50 to 70 million years ago. When the oceans receded the mud balls were exposed to sunlight and dried and cracked, the benzine content causing them to shrink, causing cracks inside. Decomposed shells seeped into these cracks and Calcite crystals (the center) were formed. The outer walls transformed into Aragonite (the brown line) and Limestone (the greyish rock).
Septarian's metaphysical properties are a combination of the minerals that it contains, making it a powerful stone. It aids in communication with Mother Earth, aids in overall healing and health, and it's a good grounding tool; it relates to the Root and Solar Plexis Chakras and aids in communication with others and promotes in being heard and understood. It's healing properties include healing of the degeneration of teeth, bones and muscles; it banishes nightmares, negative energy and blocks psychic attacks, and when held promotes the feeling of peace.