Glagolevite is a rare sodium-rich member of the chlorite group, characterized by its mica-like appearance and pearly luster. It is primarily found as platy or lamellar crystals within the alkaline-ultramafic rocks of the Kovdor Massif, and collectors should look for its distinctive pearly cleavage surfaces.
Is this glagolevite?
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 glagolevite with a known reference. Glagolevite sits at Mohs 3-5, 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 to pearly.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: triclinic. Typical habit: granular.
Often confused with
Glagolevite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Glagolevite leaves white, Clinochlore leaves greenish white to white; luster reads vitreous to pearly on Glagolevite and pearly, greasy, dull on Clinochlore.
How to tell apart: Streak differs, so Glagolevite leaves white, Chamosite leaves green to gray; luster reads vitreous to pearly on Glagolevite and pearly on Chamosite.
How to tell apart: Glagolevite is noticeably harder (Mohs 3-5 vs. 1); luster reads vitreous to pearly on Glagolevite and pearly, greasy, dull on Talc.
Often found alongside glagolevite
Minerals reported to co-occur with glagolevite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(Mg,Al)₆(Si,Al)₄O₁₀(OH,O)₈
- Mohs hardness
- 3-5
- Density
- 2.66 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to pearly
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Granular
- Cleavage
- Perfect {001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In lenses within altered melilitic rocks in a phlogopite deposit in an alkaline massif
Where rockhounds find glagolevite
Classic worldwide localities
- Kovdor Phlogopite quarry, Kovdor massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In lenses within altered melilitic rocks in a phlogopite deposit in an alkaline massif. If you start seeing pectolite, monticellite, diopside in float, you are in the right ground. Typical habit: granular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find glagolevite on the map
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