It is petrified wood. Specifically bogwood, which is swamp bog, a combination of canes, trees, algae, plants (such as cattails) and dead organisms that were in the bog when it petrified, which probably happened around 11 to 14 million years ago..
Different minerals change the coloring. For instance, the teal and bright green in this cabochon are from the presence of aluminum, calcium, iron, potassium and/or sodium.
Larsonite is a sensitive stone in the way that rhodonite is sensitive. It thrives on exquisite harmonies as well as silence. It is an excellent stones for mystics. It stimulates incredible psychic development.
Kind of a Scorpio stone in that secretive, reserved, determined and proud individuals seem especially drawn to it. It helps those individuals success and still be open to new lines of thought. Good for workaholics as it inspires a balanced life. Most workaholics feel more affectionate after carrying Larsonite around for a week.
If you feel conflicted between your heart and your mind, this stone will help you get centered so you can hear your Higher Self speak to you. It helps you to release disappointment, loss and sadness from your past.
Larsonite also teaches its owner to see difficult situations as tools for wisdom. The past gets put into perspective as less important than the here and now and the future seems brighter.
This Larsonite Jasper petrified wood cabochon is actually free-form and not a perfect oval. Lovely specimen though. It measures 21.5mm wide by 32mm long by 7.4mm thick.