Identification guide · Quartz Family
How to Identify Milky Quartz
Milky quartz is white to grayish-white and translucent to nearly opaque, with a vitreous to slightly greasy luster and a white streak. It has quartz's characteristic hardness of 7, no cleavage, and a conchoidal fracture, typically occurring as massive vein material or as hexagonal prismatic crystals with pyramidal terminations. It can be distinguished from calcite, which is much softer and effervesces in acid, and from other white minerals by its hardness and glassy fracture surfaces; its cloudy appearance separates it from clear rock crystal quartz, though both share identical chemistry.
Milky Quartz identification checklist
| Color | Milky white, White | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous, greasy | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Translucent to nearly opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 7 | 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 | 2.65 | Ordinary rock-like heft (specific gravity about 2.65), similar to quartz. |
| Crystal system | Trigonal |
Extra tests for Milky Quartz
Glass check. Milky Quartz 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.
Milky Quartz look-alikes and how to tell them apart
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Milky Quartz vs Quartz →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Milky Quartz vs Clear Quartz →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Milky Quartz vs Prasiolite →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Is my Milky Quartz real?
- Hardness: real Milky Quartz sits at Mohs 7. Glass imitations are about 5.5, so genuine Milky Quartz 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.
Milky Quartz identification FAQ
How can you tell if a rock is Milky Quartz?
Check the color (milky white and white), the vitreous, greasy luster, a Mohs hardness of 7 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Milky Quartz?
Milky Quartz has a Mohs hardness of 7. It scratches glass and a steel knife and cannot be scratched by a steel file.
What is the difference between Milky Quartz and Quartz?
Milky Quartz (Mohs 7, vitreous, greasy luster) and Quartz (Mohs 7, vitreous, greasy on fracture surfaces luster) look alike, but hardness, streak and heft usually separate them. See the full Milky Quartz vs Quartz comparison for a side-by-side table.
How do I know if my Milky Quartz is real?
Real Milky Quartz 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 Milky Quartz worth anything?
Entry-level Milky Quartz specimens sell for around $5, typical collector pieces about $35, and premium examples $250 or more depending on size, quality and locality.
What color is Milky Quartz?
Milky Quartz is most often milky white and white. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
