Pyroxferroite is a rare pyroxenoid mineral best known for its discovery in lunar basalt samples brought back by the Apollo 11 mission. It typically occurs as small yellow grains in iron-rich igneous or metamorphic environments and is a distinct high-pressure polymorph of iron silicate.
Is this pyroxferroite?
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 pyroxferroite with a known reference. Pyroxferroite sits at Mohs 4.5-5.5, 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: yellow, colorless, orange, pink orange.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, massive, granular.
Often confused with
Pyroxferroite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Pyroxferroite and pearly to vitreous on Pyroxmangite.
How to tell apart: Streak differs, so Pyroxferroite leaves white, Ferrosilite leaves pale brownish gray.
Often found alongside pyroxferroite
Minerals reported to co-occur with pyroxferroite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeSiO₃
- Mohs hardness
- 4.5-5.5
- Density
- 3.68-3.76 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals, massive, granular
- Cleavage
- Good on {010}, poor on {001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- As discrete grains in microgabbros or diabase (Sea of Tranquillity, Moon)
Where rockhounds find pyroxferroite
Classic worldwide localities
- Iva, Anderson Co., South Carolina, USA
- Sea of Tranquillity and Oceanus Procellarum, Moon
- Väster Silfberg, Värmland, Sweden
- Simsiö, Lapua, Finland
- Isanago mine, Kyoto Prefecture, Japan
Field-hunting tip
Where it forms: As discrete grains in microgabbros or diabase (Sea of Tranquillity, Moon). If you start seeing clinopyroxene, plagioclase, ilmenite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify pyroxferroite?+
Where is pyroxferroite found?+
What rocks look like pyroxferroite?+
What minerals are found with pyroxferroite?+
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What is pyroxferroite used for?+
Find pyroxferroite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
