Taseqite is an exceptionally rare silicate mineral known almost exclusively from the hyper-agpaitic rocks of the Ilimaussaq complex in Greenland. It typically forms as small, distinctive yellow-to-orange crystals in association with other rare alkaline pegmatite minerals. Due to its extreme rarity, it is primarily sought after by advanced collectors of pegmatite species.

Hardness

5.5

Mohs

Luster

Vitreous

Streak

White to light brown

Transparency

Transparent

mineralrareTundrite Group family

Taseqite

Hardness: 5.5
Luster: Vitreous
Streak: White to light brown
Transparency: Transparent

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Is this taseqite?

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 taseqite with a known reference. Taseqite sits at Mohs 5.5, 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 to light brown.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: clove brown, yellowish brown, lemon yellow.
5
Look at form & habit
Crystal system: trigonal. Typical habit: platy.

Often confused with

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

mineral

Lorenzenite

Mohs 6

How to tell apart: Streak differs, so Taseqite leaves white to light brown, Lorenzenite leaves light brownish yellow.

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Often found alongside taseqite

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

All properties

Chemical formula: Na₁₂Sr₃Ca₆Fe₃Zr₃NbSi₂₅O₇₃(O,OH,H₂O)₃Cl₂
Mohs hardness: 5.5
Density: 3.24 g/cm³
Colors: Clove brownYellowish brown Lemon yellow
Streak: White to light brown
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Platy
Cleavage: Fair on {0001}
Rarity: Rare
Uses: Collector
Host rock: In a cavity in a late-stage hydrothermal albitite vein in alkaline igneous complex

Where rockhounds find taseqite

Classic worldwide localities

Taseq slope, northern part of the the Ilímaussaq alkaline complex, Narsap Kommunea, South Greenland

Field-hunting tip

Where it forms: In a cavity in a late-stage hydrothermal albitite vein in alkaline igneous complex. If you start seeing albite, aegirine, analcime in float, you are in the right ground. Typical habit: platy. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify taseqite?+

Mohs hardness is 5.5. Luster: vitreous. The streak is white to light brown. Common colors include clove brown, yellowish brown, lemon yellow.

Where is taseqite found?+

Notable localities include Taseq slope, northern part of the the Ilímaussaq alkaline complex, Narsap Kommunea, South Greenland.

What rocks look like taseqite?+

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

What minerals are found with taseqite?+

Taseqite commonly co-occurs with Albite, Aegirine, Analcime, Ancylite-, Calcite, Catapleiite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does taseqite form in?+

Where it forms: In a cavity in a late-stage hydrothermal albitite vein in alkaline igneous complex. Working float back to the host body is the standard way to chase a fresh occurrence.

What is taseqite used for?+

Taseqite is used in collector.

Find taseqite on the map

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