Tiettaite is a rare potassium sodium iron silicate, typically grayish white. It occurs in unweathered ultra-alkalic pegmatites in an alkalic massif. It was first described from Mts. Koashva and Rasvumchorr, Khibiny massif, Kola Peninsula, Russia.

Hardness

Mohs

Luster

Vitreous or silky

Streak

White

Transparency

Transparent

mineralrare

Tiettaite

Hardness: 3
Luster: Vitreous or silky
Streak: White
Transparency: Transparent

Is this tiettaite?

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 tiettaite with a known reference. Tiettaite sits at Mohs 3, 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: vitreous or silky.
4
Match the color range
Compare against the expected color range: grayish white, colorless, dark gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: aggregates.

Often confused with

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

Often found alongside tiettaite

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

All properties

Chemical formula: K₄Na₁₂Fe³⁺₂Si₁₆O₄₁(OH)₄·2H₂O
Mohs hardness: 3
Density: 2.42 g/cm³
Colors: Grayish white Colorless Dark gray
Streak: White
Luster: Vitreous or silky
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Aggregates
Cleavage: On {100} and {010}, perfect
Rarity: Rare
Uses: Collector
Host rock: In unweathered ultra-alkalic pegmatites in an alkalic massif

Where rockhounds find tiettaite

Classic worldwide localities

Mts. Koashva and Rasvumchorr, Khibiny massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In unweathered ultra-alkalic pegmatites in an alkalic massif. If you start seeing nepheline, orthoclase, sodalite in float, you are in the right ground. Typical habit: aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tiettaite?+

Mohs hardness is 3. Luster: vitreous or silky. The streak is white. Common colors include grayish white, colorless, dark gray.

Where is tiettaite found?+

Notable localities include Mts. Koashva and Rasvumchorr, Khibiny massif, Kola Peninsula, Russia.

What rocks look like tiettaite?+

Tiettaite is most often confused with Searlesite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with tiettaite?+

Tiettaite commonly co-occurs with Nepheline, Orthoclase, Sodalite, Aegirine, Rasvumite, Natrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tiettaite form in?+

Where it forms: In unweathered ultra-alkalic pegmatites in an alkalic massif. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tiettaite used for?+

Tiettaite is used in collector.

Find tiettaite on the map

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