Petalite is a lithium-rich silicate mineral primarily found in lithium-bearing pegmatites. It is sought after by collectors for its transparent, gem-quality crystals, though it is often brittle and requires care when handled or faceted.
Is this petalite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch petalite with a known reference. Petalite sits at Mohs 6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on {001}.
- 4Match the color rangeCompare against the expected color range: colorless, gray, yellow, yellow gray, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive.
Often confused with
Petalite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside petalite
Minerals reported to co-occur with petalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- LiAlSi₄O₁₀
- Mohs hardness
- 6.5
- Density
- 2.412-2.422 g/cm³
- Streak
- White
- Luster
- Vitreous, pearly on {001}
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive
- Cleavage
- Perfect on {001}, poor on {201}; (001) ^ (201) = 38.5°
- Rarity
- Uncommon
- Uses
- Gemstone, Collector, Industrial source of lithium
- Host rock
- In granite pegmatites, locally constituting an ore of lithium
Where rockhounds find petalite
Classic worldwide localities
- Peru, Oxford Co., Maine, USA
- Bolton, Worcester Co., Massachusetts, USA
- Queen and Hiriart Mountains, Pala, and in the Clark vein at Rincon, San Diego Co., California, USA
- Island of Utö, and in the Varuträsk pegmatite, 15 km northwest of Skellefteå, Västerbotten, Sweden
- San Piero in Campo, Elba, Italy
- Hirvikallio, Tammela, and Pajula, Finland
Field-hunting tip
Where it forms: In granite pegmatites, locally constituting an ore of lithium. If you start seeing spodumene, pollucite, lepidolite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify petalite?+
Where is petalite found?+
What rocks look like petalite?+
What minerals are found with petalite?+
What kind of rock does petalite form in?+
What is petalite used for?+
Find petalite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
