Uedaite-(Ce) is a rare member of the epidote group characterized by manganese dominance in the structure. It is typically found in skarn deposits as small, dark, prismatic crystals and is primarily sought after by advanced collectors of rare earth element minerals.

Hardness
5-6
Mohs
Luster
Vitreous
Streak
Gray
Transparency
Translucent to opaque

Is this uedaite-(ce)?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch uedaite-(ce) with a known reference. Uedaite-(Ce) sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: gray.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous.
  • 4
    Match the color range
    Compare against the expected color range: dark brown, black.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: prismatic.

Often confused with

Uedaite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside uedaite-(ce)

Minerals reported to co-occur with uedaite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
MnCeAl₂Fe³⁺(Si₂O₇)(SiO₄)O(OH)
Mohs hardness
5-6
Density
4.19 g/cm³
Streak
Gray
Luster
Vitreous
Transparency
Translucent to opaque
Crystal system
Monoclinic
Crystal habit
Prismatic
Cleavage
Poor {001}
Rarity
Rare
Uses
Collector
Host rock
An accessory mineral in granite

Where rockhounds find uedaite-(ce)

Classic worldwide localities

  • Shodoshima Island, Kagawa Prefecture, Japan

Field-hunting tip

Where it forms: An accessory mineral in granite. If you start seeing allanite-, monazite-, zircon in float, you are in the right ground. Typical habit: prismatic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify uedaite-(ce)?+
Mohs hardness is 5-6. Luster: vitreous. The streak is gray. Common colors include dark brown, black.
Where is uedaite-(ce) found?+
Notable localities include Shodoshima Island, Kagawa Prefecture, Japan.
What rocks look like uedaite-(ce)?+
Uedaite-(Ce) is most often confused with Epidote, Allanite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with uedaite-(ce)?+
Uedaite-(Ce) commonly co-occurs with Allanite-, Monazite-, Zircon, Thorite, Bastnaesite-. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does uedaite-(ce) form in?+
Where it forms: An accessory mineral in granite. Working float back to the host body is the standard way to chase a fresh occurrence.
What is uedaite-(ce) used for?+
Uedaite-(Ce) is used in collector.

Find uedaite-(ce) on the map

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