Khurayyimite is an extremely rare calcium silicate mineral discovered in the pyrometamorphic rocks of the Daba-Siwaqa complex in Jordan. It typically occurs as small, colorless platy crystals associated with other rare high-temperature mineral phases. It is highly sought after by systematic mineral collectors due to its limited type locality and unique chemical composition.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Khurayyimite

Hardness: 4
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this khurayyimite?

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

Often confused with

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

How to tell apart: Rankinite is the harder of the two (Mohs 5.5 vs. 4).

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

Compare →

Often found alongside khurayyimite

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

All properties

Chemical formula: Ca₇(Si₂O₇)₂(OH)₂
Mohs hardness: 4
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy Crystals
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Metamorphic Rocks

Where rockhounds find khurayyimite

Classic worldwide localities

Khurayyim, Jordan

Field-hunting tip

Look in metamorphic rocks country, the host setting where khurayyimite typically forms. If you start seeing ettringite, portlandite, calcite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify khurayyimite?+

Mohs hardness is 4. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is khurayyimite found?+

Notable localities include Khurayyim, Jordan.

What rocks look like khurayyimite?+

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

What minerals are found with khurayyimite?+

Khurayyimite commonly co-occurs with Ettringite, Portlandite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does khurayyimite form in?+

Khurayyimite typically forms in metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is khurayyimite used for?+

Khurayyimite is used in collector.

Find khurayyimite on the map

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