Oxo-magnesio-hastingsite is a rare member of the calcic amphibole group, typically identified through sophisticated mineralogical analysis. It occurs primarily as prismatic crystals within alkaline igneous complexes. Collectors look for these dark, lustrous crystals in environments associated with iron-rich metamorphic or metasomatic processes.
Is this oxo-magnesio-hastingsite?
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 oxo-magnesio-hastingsite with a known reference. Oxo-magnesio-hastingsite sits at Mohs ~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: brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Oxo-magnesio-hastingsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Oxo-magnesio-hastingsite leaves white, Hastingsite leaves greenish gray.
How to tell apart: Streak differs, so Oxo-magnesio-hastingsite leaves white, Hornblende leaves grayish-white.
How to tell apart: Streak differs, so Oxo-magnesio-hastingsite leaves white, Magnesio-hastingsite leaves grayish white.
Often found alongside oxo-magnesio-hastingsite
Minerals reported to co-occur with oxo-magnesio-hastingsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂(Mg₂Fe³⁺₃)(Al₂Si₆)O₂₂O₂
- Mohs hardness
- ~6
- Density
- 3.19 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As reacted megacrysts in melilititic tuff derived from a silica-undersaturated alkaline magma
Where rockhounds find oxo-magnesio-hastingsite
Classic worldwide localities
- Deeti volcanic cone in the Gregory rift, northern Tanzania
Field-hunting tip
Where it forms: As reacted megacrysts in melilititic tuff derived from a silica-undersaturated alkaline magma. If you start seeing diopside, phlogopite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify oxo-magnesio-hastingsite?+
Where is oxo-magnesio-hastingsite found?+
What rocks look like oxo-magnesio-hastingsite?+
What minerals are found with oxo-magnesio-hastingsite?+
What kind of rock does oxo-magnesio-hastingsite form in?+
What is oxo-magnesio-hastingsite used for?+
Find oxo-magnesio-hastingsite on the map
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