Chayesite is a rare member of the milarite group, typically occurring as small, honey-yellow prismatic crystals. It is most prominently found within alkaline igneous complexes such as those on the Kola Peninsula, where it forms in association with sodium-rich minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareMilarite Group family

Chayesite

Hardness: 6
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this chayesite?

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 chayesite with a known reference. Chayesite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Chayesite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Chayesite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, yellow-brown.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: prismatic crystals.

Often confused with

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

Often found alongside chayesite

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

All properties

Chemical formula: KMg₄Si₁₂O₃₀
Mohs hardness: 6
Density: 2.73 g/cm³
Colors: Yellow Yellow-brown
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Prismatic Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Alkaline Igneous Rocks
Typical price: $50-300 per specimen

Where rockhounds find chayesite

Classic worldwide localities

Kola Peninsula, Russia

Field-hunting tip

Look in alkaline igneous rocks country, the host setting where chayesite typically forms. If you start seeing arfvedsonite, aegirine, microcline in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify chayesite?+

Mohs hardness is 6. It typically shows a vitreous luster. The streak is white. Common colors include yellow, yellow-brown.

Where is chayesite found?+

Notable localities include Kola Peninsula, Russia.

How much is chayesite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like chayesite?+

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

What minerals are found with chayesite?+

Chayesite commonly co-occurs with Arfvedsonite, Aegirine, Microcline, Nepheline. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does chayesite form in?+

Chayesite typically forms in alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is chayesite used for?+

Chayesite is used in collector.

Find chayesite on the map

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