Melanocerite-(Ce) is a rare silicate mineral primarily found in agpaitic alkaline igneous rocks. It typically presents as dark, resinous, rhombohedral crystals and is highly valued by collectors of rare earth element minerals.
Is this melanocerite-(ce)?
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 melanocerite-(ce) with a known reference. Melanocerite-(Ce) 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: light brown.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous to greasy.
- 4Match the color rangeCompare against the expected color range: brown, black, dark brown, reddish brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: metamict, tabular.
Often confused with
Melanocerite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Melanocerite-(Ce) leaves light brown, Gadolinite-(Y) leaves greenish gray; luster reads resinous to greasy on Melanocerite-(Ce) and vitreous to greasy on Gadolinite-(Y).
How to tell apart: Streak differs, so Melanocerite-(Ce) leaves light brown, Allanite leaves gray; luster reads resinous to greasy on Melanocerite-(Ce) and submetallic on Allanite.
Often found alongside melanocerite-(ce)
Minerals reported to co-occur with melanocerite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ce₅(SiO₄,BO₄)₃(OH,O)
- Mohs hardness
- 5-6
- Density
- 4.13-4.29 g/cm³
- Streak
- Light brown
- Luster
- Resinous to greasy
- Transparency
- Translucent, transparent in thin fragments
- Crystal system
- Hexagonal
- Crystal habit
- Metamict, tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In nepheline syenite pegmatites (Langesundsfjord, Norway); in alkalic granite pegmatites (Russia)
Where rockhounds find melanocerite-(ce)
Classic worldwide localities
- Kjeø Island, near Barkevik, Langesundsfjord, Norway
- Siberia, from the Burpala massif, about 120 km north of Lake Baikal, and on Yenisei Ridge, Russia
Field-hunting tip
Where it forms: In nepheline syenite pegmatites (Langesundsfjord, Norway); in alkalic granite pegmatites (Russia). If you start seeing astrophyllite, ferrian biotite, leucophanite in float, you are in the right ground. Typical habit: metamict, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify melanocerite-(ce)?+
Where is melanocerite-(ce) found?+
Is melanocerite-(ce) safe to handle?+
What rocks look like melanocerite-(ce)?+
What minerals are found with melanocerite-(ce)?+
What kind of rock does melanocerite-(ce) form in?+
What is melanocerite-(ce) used for?+
Find melanocerite-(ce) on the map
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