Cortesognoite is a rare calcium-vanadium silicate mineral discovered in the manganese deposits of the Molinello mine in Liguria, Italy. It typically occurs as small, brownish anhedral grains embedded within metamorphic rock matrices alongside other manganese-bearing species.
Is this cortesognoite?
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 cortesognoite with a known reference. Cortesognoite sits at Mohs 5.5-6, 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: yellowish-brown, brown.
- 4Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains and aggregates.
Often confused with
Cortesognoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Cortesognoite and adamantine to resinous on Titanite.
How to tell apart: Cortesognoite is noticeably harder (Mohs 5.5-6 vs. 4-4.5); luster reads vitreous on Cortesognoite and subadamantine to silky in aggregates on Austinite.
Often found alongside cortesognoite
Minerals reported to co-occur with cortesognoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaV₂Si₂O₇(OH)₂·H₂O
- Mohs hardness
- 5.5-6
- Colors
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains and aggregates
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- manganese-rich metamorphic rocks
Where rockhounds find cortesognoite
Classic worldwide localities
- Molinello manganese mine, Graveglia valley, Northern Apennines, Liguria, Italy
Field-hunting tip
Where it forms: manganese-rich metamorphic rocks. If you start seeing quartz, calcite, braunite in float, you are in the right ground. Typical habit: anhedral grains and aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cortesognoite?+
Where is cortesognoite found?+
Is cortesognoite safe to handle?+
What rocks look like cortesognoite?+
What minerals are found with cortesognoite?+
What kind of rock does cortesognoite form in?+
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Find cortesognoite on the map
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