Magnesio-fluoro-hastingsite is a rare member of the complex amphibole group, typically identified by its dark, prismatic crystals found in metamorphic environments. It is often indistinguishable from other dark amphiboles without advanced chemical analysis like electron microprobe testing.
Is this magnesio-fluoro-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 magnesio-fluoro-hastingsite with a known reference. Magnesio-fluoro-hastingsite sits at Mohs 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: dark green, black, brownish-black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, massive, granular.
Often confused with
Magnesio-fluoro-hastingsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Magnesio-fluoro-hastingsite leaves white, Hastingsite leaves greenish gray.
How to tell apart: Streak differs, so Magnesio-fluoro-hastingsite leaves white, Hornblende leaves grayish-white.
How to tell apart: Streak differs, so Magnesio-fluoro-hastingsite leaves white, Magnesio-hastingsite leaves grayish white.
Often found alongside magnesio-fluoro-hastingsite
Minerals reported to co-occur with magnesio-fluoro-hastingsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂Mg₄Fe³⁺(Al₂Si₆O₂₂)F₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals, massive, granular
- Cleavage
- Perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- metamorphic rocks, skarns
Where rockhounds find magnesio-fluoro-hastingsite
Classic worldwide localities
- Canada
- Italy
- Norway
- USA
Field-hunting tip
Where it forms: metamorphic rocks, skarns. If you start seeing calcite, diopside, phlogopite in float, you are in the right ground. Typical habit: prismatic crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnesio-fluoro-hastingsite?+
Where is magnesio-fluoro-hastingsite found?+
What rocks look like magnesio-fluoro-hastingsite?+
What minerals are found with magnesio-fluoro-hastingsite?+
What kind of rock does magnesio-fluoro-hastingsite form in?+
What is magnesio-fluoro-hastingsite used for?+
Find magnesio-fluoro-hastingsite on the map
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