Identification guide · Minerals
How to Identify Alabaster
Alabaster is soft enough to scratch with a fingernail, a trait that immediately separates it from marble, which resists a fingernail and needs a steel blade to mark it. It typically appears white, cream, pink, or gray with wavy veining, has a white streak, and shows a vitreous to slightly waxy, sometimes translucent luster on cut surfaces. Fracture is uneven to splintery rather than showing a clean cleavage plane in massive form. It is commonly mistaken for marble or soapstone until the fingernail test is applied.
Alabaster identification checklist
| Color | White, Cream, Pale pink, Yellowish, Gray, Banded | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous (crystalline); waxy to dull (massive) | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Translucent to opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 1.5–2 | A fingernail (Mohs 2.5) scratches it easily. |
| Streak | White | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Perfect on {010} (rarely visible in massive alabaster) | |
| Fracture | Conchoidal to splintery | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 2.3 | Ordinary rock-like heft (specific gravity about 2.3), similar to quartz. |
| Crystal system | Monoclinic |
Extra tests for Alabaster
Glass check. Alabaster 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.
Alabaster look-alikes and how to tell them apart
Both sit near Mohs 1.5–2, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Alabaster vs Gypsum →
Both sit near Mohs 1.5–2, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Alabaster vs Selenite →
Anhydrite is harder (Mohs 3–3.5) than Alabaster (Mohs 1.5–2), so Anhydrite will scratch Alabaster and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Alabaster vs Anhydrite →
Calcite is harder (Mohs 3) than Alabaster (Mohs 1.5–2), so Calcite will scratch Alabaster and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
Alabaster identification FAQ
How can you tell if a rock is Alabaster?
Check the color (white, cream, pale pink, and yellowish), the vitreous (crystalline); waxy to dull (massive) luster, a Mohs hardness of 1.5–2 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Alabaster?
Alabaster has a Mohs hardness of 1.5–2. A fingernail (Mohs 2.5) scratches it easily.
What is the difference between Alabaster and Gypsum?
Alabaster (Mohs 1.5–2, vitreous (crystalline); waxy to dull (massive) luster) and Gypsum (Mohs 2, vitreous, pearly, or silky (fibrous), earthy when massive luster) look alike, but hardness, streak and heft usually separate them. See the full Alabaster vs Gypsum comparison for a side-by-side table.
Is Alabaster worth anything?
Entry-level Alabaster specimens sell for around $2, typical collector pieces about $20, and premium examples $150 or more depending on size, quality and locality.
What color is Alabaster?
Alabaster is most often white, cream, pale pink, and yellowish. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
