Identification guide · Materials
How to Identify Goldstone
Goldstone is usually copper, brown, and orange with a vitreous luster and is opaque. It has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Its streak is white to colorless. It is most often confused with Glass, Citrine, and Grossular; the tests below separate them.
Goldstone identification checklist
| Color | Copper, Brown, Orange, Gold, Sparkly | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 5.5 | It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. |
| Streak | White to colorless | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Conchoidal | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 2.5 | Ordinary rock-like heft (specific gravity about 2.5), similar to quartz. |
| Crystal system | Amorphous |
Extra tests for Goldstone
Glass check. Goldstone shares a glassy luster and conchoidal fracture with man-made glass. Glass sits near Mohs 5.5 and often contains round gas bubbles, so a hardness test and a hand lens separate them.
Goldstone look-alikes and how to tell them apart
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Goldstone vs Glass →
Citrine is harder (Mohs 7) than Goldstone (Mohs 5.5), so Citrine will scratch Goldstone and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Goldstone vs Citrine →
Grossular is harder (Mohs 6.5–7.5) than Goldstone (Mohs 5.5), so Grossular will scratch Goldstone and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Goldstone vs Grossular →
Hessonite is harder (Mohs 6.5–7) than Goldstone (Mohs 5.5), so Hessonite will scratch Goldstone and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
Field tips
- Look for dense coppery sparkle in a glassy brown to orange body.
- Check chips or edges for glassy conchoidal fracture.
- Do not confuse Goldstone with natural Sunstone or Aventurine.
Goldstone identification FAQ
How can you tell if a rock is Goldstone?
Check the color (copper, brown, orange, and gold), the vitreous luster, a Mohs hardness of 5.5 and a white to colorless streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Goldstone?
Goldstone has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
What is the difference between Goldstone and Glass?
Goldstone (Mohs 5.5, vitreous luster) and Glass (Mohs 5.5, vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Goldstone vs Glass comparison for a side-by-side table.
Is Goldstone worth anything?
Entry-level Goldstone specimens sell for around $3, typical collector pieces about $15, and premium examples $80 or more depending on size, quality and locality.
What color is Goldstone?
Goldstone is most often copper, brown, orange, and gold. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
