Mieite-(Y) is an extremely rare yttrium-titanium mineral discovered in Japanese pegmatites. It typically occurs as small, tabular brownish-yellow crystals and is highly sought after by advanced systematic mineral collectors due to its limited distribution.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Mieite-(Y)

Hardness: 6
Luster: Adamantine
Streak: White
Transparency: Transparent

Is this mieite-(y)?

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 mieite-(y) with a known reference. Mieite-(Y) sits at Mohs 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: white.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: amber-yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals.

Often found alongside mieite-(y)

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

All properties

Chemical formula: Y₄Ti(SiO₄)₂O[F,(OH)]₆
Mohs hardness: 6
Density: 4.61 g/cm³
Colors: Amber-yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In a block of granitic pegmatite collected from a talus slope

Where rockhounds find mieite-(y)

Classic worldwide localities

Souri Valley, Komono, Mie Prefecture, central Japan
Reported from El’ozero, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In a block of granitic pegmatite collected from a talus slope. If you start seeing quartz, albite, k-feldspar in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mieite-(y)?+

Mohs hardness is 6. Luster: adamantine. The streak is white. Common colors include amber-yellow.

Where is mieite-(y) found?+

Notable localities include Souri Valley, Komono, Mie Prefecture, central Japan; Reported from El’ozero, Kola Peninsula, Russia.

What minerals are found with mieite-(y)?+

Mieite-(Y) commonly co-occurs with Quartz, Albite, K-feldspar, Muscovite, Allanite-, Gadlinite-. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mieite-(y) form in?+

Where it forms: In a block of granitic pegmatite collected from a talus slope. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mieite-(y) used for?+

Mieite-(Y) is used in collector.

Find mieite-(y) on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.