Obsidian can be an earth-stone, activating the foundation chakra and grounding you with your link to the Earth. It clears the aura of destructive Electricity, and may also be employed for scrying. In incredibly uncommon scenarios tourmaline is found in blue color, most popular being Paraiba tourmaline and indicolite tourmaline. https://andyqnjfz.wssblogs.com/30596805/detailed-notes-on-gemstones-south-africa