Sogdianite is a rare cyclosilicate belonging to the milarite group, typically found as small, vibrant violet-to-purple prismatic crystals. It is most famous from the Dara-i-Pioz area in Tajikistan and certain manganese deposits in South Africa. Collectors value it for its intense color and its unique relationship with other rare alkaline pegmatite minerals.

Hardness

5-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent to translucent

mineralrareMilarite Group family

Sogdianite

Hardness: 5-7
Luster: Vitreous
Streak: White
Transparency: Transparent to translucent

Is this sogdianite?

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 sogdianite with a known reference. Sogdianite sits at Mohs 5-7, 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.
4
Match the color range
Compare against the expected color range: violet.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: prismatic crystals.

Often confused with

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

Often found alongside sogdianite

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

All properties

Chemical formula: KZr₂Li₃Si₁₂O₃₀
Mohs hardness: 5-7
Density: 2.76-2.90 g/cm³
Colors: Violet
Streak: White
Luster: Vitreous
Transparency: Transparent to translucent
Crystal system: Hexagonal
Crystal habit: Prismatic crystals
Cleavage: {0001}, perfect
Rarity: Rare
Uses: Collector
Host rock: In a pegmatite vein with a composition about that of an alkalic granite

Where rockhounds find sogdianite

Classic worldwide localities

Washington Pass, Okanogan Co., Washington, USA
Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan
Wessels mine, near Kuruman, Cape Province, South Africa

Field-hunting tip

Where it forms: In a pegmatite vein with a composition about that of an alkalic granite. If you start seeing thorite, stillwellite, pyrochlore in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sogdianite?+

Mohs hardness is 5-7. Luster: vitreous. The streak is white. Common colors include violet.

Where is sogdianite found?+

Notable localities include Washington Pass, Okanogan Co., Washington, USA; Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan; Wessels mine, near Kuruman, Cape Province, South Africa.

What rocks look like sogdianite?+

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

What minerals are found with sogdianite?+

Sogdianite commonly co-occurs with Thorite, Stillwellite, Pyrochlore, Tienshanite, Cesium kupletskite, Microcline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sogdianite form in?+

Where it forms: In a pegmatite vein with a composition about that of an alkalic granite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sogdianite used for?+

Sogdianite is used in collector.

Find sogdianite on the map

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