Deloneite is a rare phosphate mineral member of the apatite group characterized by its strontium and sodium content. It primarily occurs as anhedral grains within alkaline igneous rock complexes and is predominantly known from the Kovdor Massif in Russia. Identification typically requires laboratory analysis due to its visual similarity to common apatite group minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareApatite Group family

Deloneite

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this deloneite?

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 deloneite with a known reference. Deloneite sits at Mohs 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: white, colorless, yellowish.
5
Look at form & habit
Crystal system: trigonal. Typical habit: anhedral grains, massive.

Often confused with

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

Often found alongside deloneite

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

All properties

Chemical formula: (Na₀.₅REE₀.₂₅Ca₀.₂₅)(Ca₀.₇₅REE₀.₂₅)Sr₁.₅(CaNa₀.₂₅REE₀.₂₅)(PO₄)₃F₀.₅(OH)₀.₅
Mohs hardness: 5
Density: 5.69 g/cm³
Colors: White Colorless Yellowish
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Anhedral grains, massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: alkaline igneous rocks

Where rockhounds find deloneite

Classic worldwide localities

Kovdor Massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: alkaline igneous rocks. If you start seeing kovdorskite, magnetite, forsterite in float, you are in the right ground. Typical habit: anhedral grains, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify deloneite?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include white, colorless, yellowish.

Where is deloneite found?+

Notable localities include Kovdor Massif, Kola Peninsula, Russia.

What rocks look like deloneite?+

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

What minerals are found with deloneite?+

Deloneite commonly co-occurs with Kovdorskite, Magnetite, Forsterite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does deloneite form in?+

Where it forms: alkaline igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is deloneite used for?+

Deloneite is used in collector.

Find deloneite on the map

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