Karasugite is a rare strontium calcium aluminum halide, typically colorless. It is a secondary mineral formed in fissures in the oxidation zone of veins of iron ores in tectonic breccias. It was first described from Tannu-Ola Mountains, Tuva, Siberia, Russia.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Karasugite

Hardness: 3-4
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this karasugite?

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 karasugite with a known reference. Karasugite sits at Mohs 3-4, 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.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Anglesite

Mohs 2.5-3

How to tell apart: Luster reads vitreous on Karasugite and adamantine, resinous to vitreous on Anglesite.

Often found alongside karasugite

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

All properties

Chemical formula: SrCaAlF₇
Mohs hardness: 3-4
Density: 3.06-3.11 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular crystals
Cleavage: Perfect on {100}, may be a parting
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral formed in fissures in the oxidation zone of veins of iron ores in tectonic breccias

Where rockhounds find karasugite

Classic worldwide localities

Karasug F–RE–barite–fluorite deposit, 15 km north of Karasug, western Tannu-Ola Mountains, Tuva, Siberia, Russia

Field-hunting tip

Where it forms: A secondary mineral formed in fissures in the oxidation zone of veins of iron ores in tectonic breccias. If you start seeing gearksutite, tikhonenkovite, fluorite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify karasugite?+

Mohs hardness is 3-4. Luster: vitreous. The streak is white. Common colors include colorless.

Where is karasugite found?+

Notable localities include Karasug F–RE–barite–fluorite deposit, 15 km north of Karasug, western Tannu-Ola Mountains, Tuva, Siberia, Russia.

What rocks look like karasugite?+

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

What minerals are found with karasugite?+

Karasugite commonly co-occurs with Gearksutite, Tikhonenkovite, Fluorite, Barian celestine, Limonite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does karasugite form in?+

Where it forms: A secondary mineral formed in fissures in the oxidation zone of veins of iron ores in tectonic breccias. Working float back to the host body is the standard way to chase a fresh occurrence.

What is karasugite used for?+

Karasugite is used in collector.

Find karasugite on the map

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