Obsidian is an amorphous stone. Its structure contains no regular geometric pattern. Obsidian has been described as either volcanic glass or rock. The gemstone is named after an ancient Roman who was known as Obsius. Not much is known about him.
In the past, obsidian was used to manufacture cutting and piercing tools. It has also been used experimentally as a surgical scalpel blade. Pure obsidian is typically dark in appearance. The colour, however, varies depending on the impurities present.
Modern archaeologists developed a relative dating system called obsidian hydration to calculate the age of obsidian artefacts. The first known archaeological evidence of the usage of obsidian was in Kariandusi (Kenya).
Native American people traded obsidian throughout the Americas. Each volcano and each volcanic eruption produced a distinguishable type of obsidian. This allowed archaeologists to trace the origins of a particular artefact.
In the modern context, obsidian can be used to fashion extremely sharp knives. Obsidian blades are made using naturally occurring obsidian instead of manufactured glass. One major disadvantage of the obsidian blade is their brittleness in comparison to those made of metal. This limits the surgical applications for obsidian blades.
Rainbow Obsidian
Rainbow obsidian is black obsidian that, when polished and exposed to light, reveals a band of different colours. The colours correspond to layers of molten lava that cooled at different time periods.
In dim light, a rainbow obsidian stone may appear to be pure black. When light shines upon it, radiant and vivid rings of colour appear.
It is believed that meditating with obsidian can facilitate the light that emerges at the end of a long meditative journey. This light is a metaphor for the hope, illumination and energy that comes through after we work through our most blocked and stagnant areas.
Some believe that obsidian can be placed over the heart to stabilise our emotions during periods of stress and upheaval. Due to its dark colour, it is associated with the root chakra. However, what rainbow obsidian does is bring hope, illumination and energy into the areas of the physical body that are most blocked, stagnant and even stuck.
While a stone can never work miracles, the One who created the stone is miraculous, indeed.
The Mercantile 
