Identification guide · Silicate Minerals
How to Identify Moss Agate
Moss Agate is usually colorless, white, and green with a vitreous luster and is translucent. It has a Mohs hardness of 6.75. It scratches glass and a steel knife and cannot be scratched by a steel file. Its streak is white. It is most often confused with Chalcedony, Onyx, and Quartz; the tests below separate them.
Moss Agate identification checklist
| Color | Colorless, White, Green, Brown, Black | 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 | Translucent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 6.75 | It scratches glass and a steel knife and cannot be scratched by a steel file. |
| Streak | White | 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 | 2.62 | Ordinary rock-like heft (specific gravity about 2.62), similar to quartz. |
| Crystal system | Trigonal |
Extra tests for Moss Agate
Glass check. Moss Agate 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.
Moss Agate look-alikes and how to tell them apart
Both sit near Mohs 6.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Moss Agate vs Chalcedony →
Both sit near Mohs 6.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Moss Agate vs Onyx →
Both sit near Mohs 6.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Moss Agate vs Quartz →
Both sit near Mohs 6.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Is my Moss Agate real?
- Hardness: real Moss Agate sits at Mohs 6.75. Glass imitations are about 5.5, so genuine Moss Agate scratches glass while a glass fake cannot.
- Bubbles: round gas bubbles under a 10x loupe mean glass or resin, never a natural stone.
- Color: dyed material concentrates color in cracks and pores; look for pigment collecting at the edges of fractures.
- Temperature: natural crystals feel cool and take longer to warm in your hand than plastic or resin.
Field tips
- Look for translucent chalcedony with green, brown, or black branching inclusions resembling moss or foliage.
- Moss agate is hard at about 6.5 to 7 with conchoidal fracture and no cleavage.
- Unlike classic agate it lacks concentric bands; the pattern comes from scattered mineral inclusions.
Moss Agate identification FAQ
How can you tell if a rock is Moss Agate?
Check the color (colorless, white, green, and brown), the vitreous luster, a Mohs hardness of 6.75 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Moss Agate?
Moss Agate has a Mohs hardness of 6.75. It scratches glass and a steel knife and cannot be scratched by a steel file.
What is the difference between Moss Agate and Chalcedony?
Moss Agate (Mohs 6.75, vitreous luster) and Chalcedony (Mohs 6.5–7, waxy to vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Moss Agate vs Chalcedony comparison for a side-by-side table.
How do I know if my Moss Agate is real?
Real Moss Agate matches the hardness listed above, shows no round gas bubbles under magnification, and does not concentrate dye in cracks. Glass and resin fakes fail at least one of those checks.
Is Moss Agate worth anything?
Entry-level Moss Agate specimens sell for around $5, typical collector pieces about $30, and premium examples $150 or more depending on size, quality and locality.
What color is Moss Agate?
Moss Agate is most often colorless, white, green, and brown. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
