How to Tell if Obsidian Is Real

How to tell if obsidian is real can be surprisingly difficult because obsidian itself is a natural glass. Unlike identifying a crystalline gemstone from ordinary manufactured glass, the distinction here is between volcanic glass formed naturally and glass or other materials produced or altered by people.

In Part 1 of our Obsidian Learning Series, we explored how obsidian forms when silica-rich molten material cools rapidly enough to prevent a conventional crystal structure from developing. We also looked at genuine varieties including black obsidian, gold sheen obsidian, silver sheen obsidian, snowflake obsidian, and mahogany obsidian.

Now we can tackle the practical question: when something is being sold as obsidian, what should you actually look for?

Why Obsidian Can Be Difficult to Authenticate

Natural obsidian and manufactured glass share several characteristics. Both are amorphous rather than conventionally crystalline, both can have a glassy luster, and both can fracture in a similar curved pattern known as conchoidal fracture.

This means that simply saying a specimen "looks like glass" tells us very little. Genuine obsidian is supposed to look glassy.

Color is not enough either. Natural black obsidian can appear remarkably uniform, particularly when highly polished into beads, cabochons, spheres, or carvings.

A reliable identification therefore depends on examining several characteristics together rather than relying on one home test.

What Does Natural Black Obsidian Look Like?

Black obsidian typically has a smooth, vitreous or glass-like luster when polished. Larger pieces may look nearly opaque, while thinner edges can sometimes transmit light and reveal brownish, smoky, or other subtle undertones.

Natural material can contain flow structures, tiny mineral inclusions, gas bubbles, or variations created during its volcanic formation. However, these features are not necessarily visible in every finished piece.

That is especially true with small polished beads.

Perfectly smooth black beads should therefore not automatically be considered fake simply because obvious inclusions cannot be seen. Cutting and polishing can produce extremely clean-looking surfaces from genuine volcanic glass.

Understanding Gold Sheen and Silver Sheen Obsidian

Gold sheen and silver sheen obsidian can provide more obvious internal features than ordinary black material.

The reflective appearance is produced by microscopic structures within the volcanic glass that interact with light. When the stone is rotated, the sheen may strengthen, weaken, or appear to move across the surface.

Because the effect depends on orientation, two beads cut from the same rough material may show different amounts of sheen.

This natural variation can be useful when examining a strand. Genuine gemstone beads do not necessarily need to display identical reflections from bead to bead.

At the same time, visual appearance alone should not be treated as definitive proof of authenticity.

Snowflake Obsidian Has a Different Story

Snowflake obsidian is recognizable by pale gray to whitish patterns scattered through a darker glassy background.

These markings are not paint or surface decoration. They result from crystalline aggregates—commonly associated with cristobalite—that develop within the volcanic glass.

Patterns can vary considerably in size, concentration, and distribution. Some pieces contain numerous prominent "snowflakes," while others display smaller or more widely spaced formations.

Because these features occur within the material, examining them under magnification can provide useful information about the stone's structure.

Be Careful with Unusual "Obsidian" Colors

This is one of the most important areas for buyers to understand.

Black, mahogany, snowflake, gold sheen, and silver sheen are well-established natural obsidian appearances. But the marketplace also contains brightly colored transparent glass sold under names containing the word "obsidian."

Vivid transparent blue, green, yellow, and other unusually bright materials deserve additional scrutiny when represented as naturally occurring obsidian.

A creative trade name is not the same thing as a gemological identification.

When encountering unusually colored "obsidian," ask what the material actually is, whether the color is natural, whether it has been treated, and whether the seller can substantiate the description.

This is especially important online, where photographs and trade terminology can make manufactured glass appear much more exotic than it actually is.

Can Bubbles Tell You if Obsidian Is Real?

Not by themselves.

Gas bubbles can occur in natural volcanic glass, but bubbles can also occur in manufactured glass.

Their presence therefore does not automatically prove that a specimen is either natural or artificial.

The shape, distribution, surrounding structures, and other microscopic characteristics must be considered together. This is one reason gemologists use magnification as part of a broader examination rather than relying on a single inclusion.

The same principle applies to many supposed at-home obsidian tests: one observation rarely provides a definitive answer.

Should You Use a Scratch Test?

Scratch tests are frequently suggested online for identifying gemstones, but they are not a good approach for finished obsidian.

Obsidian is around 5 to 5.5 on the Mohs hardness scale. Scratching a polished bead, carving, cabochon, or piece of jewelry can permanently damage its surface while still failing to provide a definitive identification.

Temperature or "cold-to-the-touch" tests are similarly unreliable. Many materials can initially feel cool depending on their surroundings, size, and thermal properties.

Destructive tests are particularly unnecessary when professional identification methods can examine a specimen without intentionally damaging it.

How Gemologists Identify Obsidian

A gemologist approaches identification by examining multiple properties.

Visual examination and magnification may reveal flow structures, inclusions, bubbles, surface characteristics, or evidence inconsistent with natural volcanic glass. Optical and physical properties can provide additional information, while more advanced laboratory analysis may be appropriate for difficult or valuable specimens.

Context can matter as well. A documented geological source provides information that an unexplained brightly colored object sold online does not.

Most importantly, professional identification does not depend on one dramatic trick. It builds a conclusion from several pieces of evidence.

What Should You Ask Before Buying Obsidian?

Before purchasing obsidian—especially unusual colors or expensive collector pieces—look carefully at how the seller describes the material.

Is it identified as natural obsidian?

Is a geographic source provided, and is that origin known rather than assumed?

If the stone has an unusual color or optical effect, is that appearance natural?

Has any treatment been disclosed?

For gemstone beads, natural variation can also be informative. Differences in sheen, pattern, transparency, and tone are normal characteristics of many natural materials and should not automatically be viewed as defects.

Clear disclosure is more valuable than an impressive trade name.

Natural Obsidian vs. Manufactured Glass

Perhaps the most important lesson from this two-part series is that obsidian's glass-like appearance is not something that makes it suspicious—it is exactly what makes obsidian scientifically interesting.

Obsidian is natural volcanic glass.

The challenge is determining whether that glass formed through volcanic processes or was manufactured, altered, or marketed under an inaccurate name.

Black color alone cannot answer that question. Neither can bubbles, temperature, a scratch test, or one photograph.

Understanding how genuine obsidian forms, recognizing its established natural varieties, questioning unusual trade names, and seeking professional identification when necessary provide a much stronger foundation for buying confidently.

Together, our two-part Obsidian Learning Series answers both sides of the story: what obsidian actually is and how to evaluate whether the material being offered as obsidian is genuinely natural.