Ephesite is a rare brittle mica that typically occurs as thin, platy crystals or foliated masses. It is primarily identified by its occurrence in specific metamorphic environments like emery deposits and its distinct association with corundum and diaspore.
Is this ephesite?
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 ephesite with a known reference. Ephesite sits at Mohs 3.5-4, 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, pearly on cleavage.
- 4Match the color rangeCompare against the expected color range: brownish pink, pearl gray, pale green.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, micaceous aggregates.
Often confused with
Ephesite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous, pearly on cleavage on Ephesite and pearly on cleavage, vitreous on lateral faces on Margarite.
How to tell apart: Luster reads vitreous, pearly on cleavage on Ephesite and pearly to vitreous on Lepidolite.
Often found alongside ephesite
Minerals reported to co-occur with ephesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaLiAl₂(Al₂Si₂)O₁₀(OH)₂
- Mohs hardness
- 3.5-4
- Density
- 2.984 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous, pearly on cleavage
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy crystals, micaceous aggregates
- Cleavage
- {001}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In an emery deposit (Gumuch-dagh, Turkey); a minor constituent in manganese oxide ore (Postmasburg district, South Africa)
Where rockhounds find ephesite
Classic worldwide localities
- Original locality at Gumuch-dagh, near Ephesus, Turkey was later determined to be a mixture, but has not been reexamined by modern methods
- Lohatla, Postmasburg district, Transvaal, and in the Wessels mine, near Kuruman, Cape Province, South Africa
Field-hunting tip
Where it forms: In an emery deposit (Gumuch-dagh, Turkey); a minor constituent in manganese oxide ore (Postmasburg district, South Africa). If you start seeing corundum, magnetite, diaspore in float, you are in the right ground. Typical habit: platy crystals, micaceous aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ephesite?+
Where is ephesite found?+
What rocks look like ephesite?+
What minerals are found with ephesite?+
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What is ephesite used for?+
Find ephesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
