Sazhinite-(La) is a rare lanthanum-dominant silicate mineral found in hyper-alkaline igneous environments. It typically forms thin, tabular crystals or radiating sprays within pegmatitic cavities in nepheline syenites. It is highly sought after by systematic mineral collectors due to its status as a rare earth element-bearing species.

Hardness

Mohs

Luster

Vitreous to pearly

Streak

White

Transparency

Translucent

mineralrare

Sazhinite-(La)

Hardness: 3
Luster: Vitreous to pearly
Streak: White
Transparency: Translucent

Is this sazhinite-(la)?

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 sazhinite-(la) with a known reference. Sazhinite-(La) 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 to pearly.
4
Match the color range
Compare against the expected color range: creamy white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: euhedral crystals.

Often confused with

Sazhinite-(La) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Apophyllite is the harder of the two (Mohs 4-5 vs. 3).

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Often found alongside sazhinite-(la)

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

All properties

Chemical formula: Na₃LaSi₆O₁₅(H₂O)₂
Mohs hardness: 3
Density: 2.42 g/cm³
Colors: Creamy white
Streak: White
Luster: Vitreous to pearly
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Euhedral crystals
Cleavage: Good on {010}; good on {001}
Rarity: Rare
Uses: Collector
Host rock: Occurs in vesicles within the phonolite, together with other species crystallized from late-stage hydrothermal fluids

Where rockhounds find sazhinite-(la)

Classic worldwide localities

Aris phonolite intrusion, Windhoek, Namibia (type locality)

Field-hunting tip

Where it forms: Occurs in vesicles within the phonolite, together with other species crystallized from late-stage hydrothermal fluids. If you start seeing microcline, aegirine, eudialyte in float, you are in the right ground. Typical habit: euhedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sazhinite-(la)?+

Mohs hardness is 3. Luster: vitreous to pearly. The streak is white. Common colors include creamy white.

Where is sazhinite-(la) found?+

Notable localities include Aris phonolite intrusion, Windhoek, Namibia (type locality).

What rocks look like sazhinite-(la)?+

Sazhinite-(La) is most often confused with Sazhinite-(Ce), Apophyllite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with sazhinite-(la)?+

Sazhinite-(La) commonly co-occurs with Microcline, Aegirine, Eudialyte, Arfvedsonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sazhinite-(la) form in?+

Where it forms: Occurs in vesicles within the phonolite, together with other species crystallized from late-stage hydrothermal fluids. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sazhinite-(la) used for?+

Sazhinite-(La) is used in collector.

Find sazhinite-(la) on the map

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