Moganite is a polymorph of silica that occurs as a microcrystalline intergrowth within chalcedony and agate. It is difficult to distinguish from quartz without advanced laboratory methods like X-ray diffraction, often appearing as an inconspicuous grayish component of common chalcedony.
Is this mogánite?
4-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 mogánite with a known reference. Mogánite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 3Match the color rangeCompare against the expected color range: gray.
- 4Look at form & habitCrystal system: monoclinic. Typical habit: microcrystalline aggregates.
Often confused with
Mogánite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mogánite
Minerals reported to co-occur with mogánite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂·nH₂O
- Mohs hardness
- 6
- Density
- 2.52-2.58 g/cm³
- Colors
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Microcrystalline aggregates
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Scientific research
- Host rock
- A common component of agate, chert, flint
Where rockhounds find mogánite
Classic worldwide localities
- Mogán, Grand Canary Island, Spain (type locality)
Field-hunting tip
Where it forms: A common component of agate, chert, flint. If you start seeing quartz, chalcedony, opal in float, you are in the right ground. Typical habit: microcrystalline aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mogánite?+
Where is mogánite found?+
What rocks look like mogánite?+
What minerals are found with mogánite?+
What kind of rock does mogánite form in?+
What is mogánite used for?+
Find mogánite on the map
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