Purple Sheen Obsidian
Volcanic glass (silica-rich, ~70-75% SiO2, amorphous)
Black volcanic glass that reveals a soft purple-to-violet sheen at certain angles, caused by light interference off aligned inclusions.
- Mohs hardness
- 5-5.5
- Color
- Black with purple-to-violet sheen
- Type
- igneous
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Overview
Purple Sheen Obsidian is a variety of obsidian that displays a subtle purple-to-violet shimmer floating over a black glassy body when light catches it at the right angle. It belongs to the family of 'sheen' obsidians along with silver-sheen and gold-sheen varieties.
The stone is ordinary black volcanic glass; the purple effect is purely optical, produced by thin, aligned layers of nanoscale inclusions or gas bubbles that scatter and interfere with light.
Unlike body-colored stones, the purple appears only as a reflective sheen, not as a transparent purple color, which helps distinguish genuine sheen obsidian from dyed or manufactured glass.
Formation & geology
Purple Sheen Obsidian forms like all obsidian, by the rapid cooling of silica-rich lava into an amorphous glass. As the lava flowed, microscopic inclusions, such as tiny gas bubbles or mineral nanoparticles, became aligned along flow planes.
Light reflecting off these closely spaced, parallel layers undergoes interference and scattering, producing a colored sheen. Slight differences in layer spacing yield silver, gold, blue, green, or purple sheens. The sheen follows the orientation of the inclusion layers, so the effect is directional and varies as the stone is turned.
How to identify it
Identify the base as obsidian: conchoidal fracture, vitreous luster, hardness ~5-5.5, white streak. The diagnostic feature is a purple sheen, a metallic-looking shimmer that floats across the surface and shifts with angle, rather than a transparent purple body color.
Tilt the stone in good light; the sheen should sweep across the polished face.
Look-alikes: dyed or manufactured purple glass (uniform transparent color, round bubbles), charoite and lepidolite (crystalline purple minerals, different textures), and amethyst (transparent crystalline quartz, hardness 7). Sheen, not body color, marks true purple sheen obsidian.
Uses & significance
Purple Sheen Obsidian is cut into cabochons, spheres, beads, and tumbled stones oriented to display the sheen. It is a desirable but affordable ornamental material, with well-defined sheen pieces fetching more than plain obsidian.
It is used mainly in jewelry and decorative objects.
Metaphysically it is associated with intuition, calm, and spiritual insight; such claims are not scientifically established. Its appeal lies in the elusive, shifting purple glow.
Frequently asked questions
What causes the purple sheen?
Aligned layers of microscopic gas bubbles or mineral inclusions reflect and interfere with light, producing a directional purple shimmer over the black glass.
Is the purple a real color or a sheen?
It is a sheen, an angle-dependent optical effect, not a transparent purple body color. Genuine pieces are black with a floating purple shimmer.
How is it different from dyed purple glass?
Dyed or manufactured glass shows uniform transparent purple and often round bubbles, while sheen obsidian is black with a directional shimmer and conchoidal fracture.
Is Purple Sheen Obsidian related to gold and silver sheen obsidian?
Yes, they are the same kind of obsidian; the sheen color depends on the spacing of the aligned inclusion layers.
Purple Sheen Obsidian guides
In-depth guides for identifying, valuing, and understanding Purple Sheen Obsidian.
