Ertixiite is an extremely rare sodium silicate mineral known almost exclusively from its type locality at the Koktokay pegmatite in China. It typically occurs as small, clear, equant crystals associated with lithium-bearing pegmatite minerals. Due to its extreme rarity, it is highly sought after by advanced systematic mineral collectors.

Hardness

5.8-6.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Ertixiite

Hardness: 5.8-6.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this ertixiite?

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 ertixiite with a known reference. Ertixiite sits at Mohs 5.8-6.5, 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.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: cubic. Typical habit: granular.

Often confused with

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

Often found alongside ertixiite

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

All properties

Chemical formula: Na₂Si₄O₉
Mohs hardness: 5.8-6.5
Density: 2.35 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Granular
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As linings of miarolitic cavities in a Ta-Nb-Be-bearing granite pegmatite

Where rockhounds find ertixiite

Classic worldwide localities

Altay pegmatite mine, Fuyun Co., 600 km northeast of Urumchi, Sinkiang Uighur Autonomous Region, China

Field-hunting tip

Where it forms: As linings of miarolitic cavities in a Ta-Nb-Be-bearing granite pegmatite. If you start seeing topaz, albite, muscovite in float, you are in the right ground. Typical habit: granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ertixiite?+

Mohs hardness is 5.8-6.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is ertixiite found?+

Notable localities include Altay pegmatite mine, Fuyun Co., 600 km northeast of Urumchi, Sinkiang Uighur Autonomous Region, China.

What rocks look like ertixiite?+

Ertixiite is most often confused with Quartz, Albite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ertixiite?+

Ertixiite commonly co-occurs with Topaz, Albite, Muscovite, Quartz, Apatite, Garnet. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ertixiite form in?+

Where it forms: As linings of miarolitic cavities in a Ta-Nb-Be-bearing granite pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ertixiite used for?+

Ertixiite is used in collector.

Find ertixiite on the map

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