Pertlikite is a very rare member of the garnet group specifically occurring as a secondary mineral in volcanic cavities. Collectors typically find it as small, yellowish-dark olive-green to black dodecahedral crystals associated with quartz and calcite within basaltic host rocks.
Is this pertlikite?
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 pertlikite with a known reference. Pertlikite sits at Mohs 7-7.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pertlikite leaves a grayish green streak.
- 3Read the lusterHold the specimen under a strong light. Pertlikite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark olive-green, black.
- 5Look at form & habitCrystal system: tetragonal.
Often confused with
Pertlikite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Pertlikite leaves grayish green, Grossularite Garnet leaves white.
How to tell apart: Streak differs, so Pertlikite leaves grayish green, Andradite leaves white; luster reads vitreous on Pertlikite and adamantine to resinous to dull on Andradite.
Often found alongside pertlikite
Minerals reported to co-occur with pertlikite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂(Fe²⁺,Mg)₂(Mg,Fe³⁺)₄Fe³⁺₂Al(SO₄)₁₂·18H₂O
- Mohs hardness
- 7-7.5
- Density
- 2.59 g/cm³
- Colors
- Streak
- Grayish Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Amygdaloidal Basalt Cavities
Where rockhounds find pertlikite
Classic worldwide localities
- Madeni Zakh, Iran
Field-hunting tip
Look in amygdaloidal basalt cavities country, the host setting where pertlikite typically forms. If you start seeing quartz, calcite, hematite in float, you are in the right ground.
Common questions
How do you identify pertlikite?+
Where is pertlikite found?+
What rocks look like pertlikite?+
What minerals are found with pertlikite?+
What kind of rock does pertlikite form in?+
What is pertlikite used for?+
Find pertlikite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
