This piece of Mahogany obsidian perfectly demnstrates how this material earns its name. A beautiful deep black and red colour, this is a type of natural glass which is formed when lava and water wix under the correct circumstances. 
 
Tumblestone mahogany obsidian is more difficult to verify because it doesn't have the natural cleavage to examine in order to properly id it. Obsidian has the same cleavage as glass anyway - but it is often less jagged when it breaks. That breakage is harder to imitate. 
 
This piece came from an old crystal collection bought in 2025. It has been washed in hot, soapy water, bathed in nag champa incense, and is ready to be rehomed.
 
The rough mahogany obsidian goes for slightly more than the tumbled stones do but this is a preloved mineral so you always get a good deal.
 
I also wanted to add for crystal healers or energy users that obsidian is what fills in for moldavite when it decides to take a summer holiday.