Virgilite is a rare lithium-aluminosilicate mineral primarily identified in volcanic glassy matrices. It often occurs as microscopic inclusions or fine-grained aggregates within rhyolitic rocks and is highly valued by mineralogists for its unique structural relationship to the spodumene group.
Is this virgilite?
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 virgilite with a known reference. Virgilite sits at Mohs 5.5-6, 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.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: inclusions.
Often confused with
Virgilite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside virgilite
Minerals reported to co-occur with virgilite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- LiₓAlₓSi₃₋ₓO₆
- Mohs hardness
- 5.5-6
- Density
- 2.46 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Inclusions
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- As inclusions in stream cobbles of peraluminous volcanic glass
Where rockhounds find virgilite
Classic worldwide localities
- From near Macusani, Puno Department, Peru (type locality)
Field-hunting tip
Where it forms: As inclusions in stream cobbles of peraluminous volcanic glass. If you start seeing quartz, andalusite, sillimanite in float, you are in the right ground. Typical habit: inclusions. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify virgilite?+
Where is virgilite found?+
What rocks look like virgilite?+
What minerals are found with virgilite?+
What kind of rock does virgilite form in?+
What is virgilite used for?+
Find virgilite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
