Raw Opals

The value of raw opal is not fixed at a single price—it depends on its grading. Everything hinges on its quality—specifically, the intensity of its "play-of-color" (rainbow effect), its transparency, its carat weight, and the clarity of the stone. Basic raw opal can be acquired quite cheaply, but high-quality opal—especially pieces that exhibit bright, vivid colors—can be quite expensive. Origin also plays a significant role; opal from certain regions is naturally more valuable than that from others.

Key Factors

Play-of-color (the most important factor)

Body tone (darker opals tend to be more valuable)

Cracks / Inclusions (excessive flaws reduce the stone's value)

Origin—Ethiopian opal is generally more affordable, whereas high-end Australian opal commands a premium price.

To identify raw opal, first observe its natural appearance; it is typically rough and uneven, rather than perfectly smooth. If it displays flashes of color (resembling a rainbow effect) when light strikes it, that is a strong indication of authenticity. Fake stones often appear overly perfect or have a plastic-like look and feel. Genuine opal feels slightly cool to the touch, and its internal pattern is natural and random—it does not exhibit repetitive or uniform patterns.

Basic visual tricks are often insufficient for identifying raw opal; a slightly more technical examination is required:

Check the Structure

Natural opal is often found attached to its host rock (known as the "matrix").

A raw stone that appears absolutely "perfectly clean" should be viewed with suspicion.

Play-of-Color Test

Move the stone relative to the light source—the colors should shift and change.

Static or painted-looking colors suggest a high probability that the stone is fake.

Surface Feel

It should have a waxy or glassy texture.

A lightweight, plastic-like feel is indicative of a fake stone.

Water Test 

Ethiopian opal, in particular, tends to absorb water (due to its "hydrophane" nature).

Fake stones typically remain unaffected by water.

Pattern Randomness

The pattern of a real opal never repeats itself.

In artificial stones, a repetitive pattern is often found.

Raw Ethiopian opal is so popular because it typically displays bright and vibrant colors—sometimes accompanied by very strong "fire" (rainbow-like flashes). Furthermore, it is relatively affordable compared to other high-end opals, making it attractive to both beginners and collectors alike. People also appreciate its unique appearance and the variety it offers.

A genuine raw opal stone clearly exhibits the following characteristics:

Amorphous silica structure (it is not crystalline)

Water content (3–20%)

Irregular fracture (conchoidal break)

Play-of-color (if it is a precious opal)

Presence of matrix (host rock may remain attached)

No sharp crystal edges (because it is not crystalline)

Important: Not every raw opal displays a "play-of-color"—this feature is found only in "precious opals." The rest are classified as "common opals."

This is the most crucial part—it is where people make the most mistakes. It is essential to exercise caution when purchasing raw opal. Check for the following points:

1. Rough appearance vs. actual potential

What you see isn't always what you get—the color may actually disappear once the stone is cut.

2. Cracks (Crazing)

Fine cracks indicate that the stone could break in the future.

3. Lighting check

View the seller's video from various angles.

Sellers often mislead buyers by showcasing the stone from only one brightly lit angle.

4. Weight vs. usable material

The entire weight of a raw stone does not necessarily represent usable material.

5. Treatment disclosure

Verify whether the stone has undergone any dye or smoke treatments.

6. Source credibility

Be wary of random sellers on Instagram, and always check the seller's return policy. If possible, request a video or multiple photographs—do not rely solely on a single image. Furthermore, if the price seems unusually low, you should definitely be suspicious.