Roedderite is a rare member of the osumilite group found primarily in inclusions within volcanic rocks. It typically occurs as small colorless or white tabular crystals that are difficult to distinguish from other silicates without chemical analysis.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareOsumilite Group family

Roedderite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this roedderite?

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 roedderite with a known reference. Roedderite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Roedderite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Roedderite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: tabular crystals, anhedral grains.

Often confused with

Roedderite vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Sugilite is the harder of the two (Mohs 6-6.5 vs. 5).

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Often found alongside roedderite

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

All properties

Chemical formula: (Na,K)₂Mg₅Si₁₂O₃₀
Mohs hardness: 5
Density: 2.66 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Tabular Crystals, Anhedral Grains
Cleavage: Poor
Rarity: Rare
Uses: Collector
Host rock: Xenoliths in Volcanic Rocks
Typical price: $50-300 per specimen

Where rockhounds find roedderite

Classic worldwide localities

Koneprusy, Czech Republic
Bellerberg Volcano, Germany
Khibiny Massif, Russia

Field-hunting tip

Look in xenoliths in volcanic rocks country — that is the host setting where roedderite typically forms. If you start seeing sanidine, diopside, leucite in float, you are in the right ground. Field specimens usually show a tabular crystals, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify roedderite?+

Mohs hardness is 5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is roedderite found?+

Notable localities include Koneprusy, Czech Republic; Bellerberg Volcano, Germany; Khibiny Massif, Russia.

How much is roedderite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like roedderite?+

Roedderite is most often confused with Osumilite, Merrihueite, Sugilite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with roedderite?+

Roedderite commonly co-occurs with Sanidine, Diopside, Leucite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does roedderite form in?+

Roedderite typically forms in xenoliths in volcanic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is roedderite used for?+

Roedderite is used in collector.

Find roedderite on the map

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