Customers reach out to me over video calls all the time, holding up a black bracelet and asking one simple question: "Is this obsidian real?" Obsidian is naturally-formed volcanic glass, and it's surprisingly easy to copy using man-made black glass. Both are made mostly of silicon dioxide, and neither has a fixed crystalline structure. New buyers can easily get tricked just by looking at the surface alone. I work with these stones day-in and day-out at our factory, so today I'm walking you through the common obsidian varieties and the ways I actually spot the fakes — no crystal folklore, just what works in practice.
First, know the types: obsidian comes in a few common kinds
Obsidian covers quite a few different varieties. Below are the main types you will run into on the market. Once you learn them, you won't lump every dark-colored stone together:
| Type | What it looks like |
|---|---|
| Black (Wu Jin) obsidian | Opaque, solid jet-black base — the most widely available variety |
| Gold / Silver sheen obsidian | Aligned mineral inclusions create shimmering gold or silver reflections. Cat's-eye chatoyant pieces are considered top-grade |
| Rainbow obsidian | Thin surface layers produce shifting rainbow flashes when you tilt the stone under light |
| Ice obsidian | Semi-translucent; light can shine through thin edges, with a softer, watery-looking texture |
The most practical test: the backlight color check
Nearly every fake obsidian out there is nothing more than colored black glass. Here is an extremely simple trick that can rule out most glass imitations: hold your stone over a phone flashlight or screen, and watch what color light shines through it.
- If transmitted light glows blue, purple, or red → it's artificial black glass.
- If you get a yellow-brown, yellow-green tint, or barely any noticeable color shift → you're most likely looking at genuine obsidian.
The reasoning comes down to how each material gets its dark color. Manufactured black glass is usually colored with transition-metal additives, cobalt being one of the most common. These chemicals filter certain light wavelengths, giving that cool blue, purple or red hue when backlit. Real obsidian contains almost none of those colorants. Light passing through it keeps a warm yellow-brown tone with no weird color distortion. If shining a light through it brings up an unexpected tint, treat it as a major red flag.
Next, inspect the interior: natural obsidian is never perfectly flawless
Don't stop at the backlight test. Take a closer look at what's inside your stone. Natural obsidian often contains mineral impurities or flow band marks left behind during volcanic cooling. Magnified, it will always show some form of internal texture. Glass fakes, on the other hand, tend to be completely uniform and unnaturally clean. Combine this check with your backlight test, and you can avoid nearly all basic fakes.
Rainbow obsidian specifically: check if the shimmer moves
Rainbow obsidian is frequently altered with surface treatments. The key detail to watch for is movement. Natural rainbow flash is soft and uneven; it shifts and dances as you rotate the stone and change the lighting angle. Treated rainbow obsidian usually has overly bright, flat shimmer that sits right on the surface, and looks almost identical no matter how you twist it.
Let's keep things realistic: raw obsidian is not a high-priced gemstone, so financially there's far less incentive to fake it compared to amethyst or citrine. Even so, black-glass knock-offs are still widespread, especially among those ultra-cheap, glossy all-black bracelets sold online. Keep in mind: surface-treated material is not automatically a scam — the problem arises when sellers hide those treatments from buyers. If your backlight test returns a strange tint and the stone looks suspiciously spotless, pause before buying. Feel free to reach out if you would like a second opinion.
None of these checks rely on metaphysical properties. Obsidian is volcanic glass mixed with iron traces and natural inclusions; fake black glass is artificially pigmented and unnaturally consistent. Once you get that core difference, the rest of the tests just fall into place. We handle genuine obsidian stock and run side-by-side comparisons on a daily basis here at the factory, if you'd like to view our available inventory.
Related reading: our guide to natural vs synthetic amethyst, our guide to natural vs irradiated citrine, or our guide to wholesaling natural crystals from China. You can also browse our natural crystal collection.
