Ikaite is a rare, metastable mineral that exists only at very low temperatures near freezing point, typically found in marine sediments and polar regions. It is highly unstable and will dehydrate into calcite if removed from its cold environment or allowed to warm, making it a challenging mineral to preserve in collections.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareCalcite Group family

Ikaite

Hardness: 2.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this ikaite?

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 ikaite with a known reference. Ikaite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Ikaite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Ikaite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, gray, yellowish.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: pseudomorphs, bladed crystals, tabular.

Often confused with

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

Often found alongside ikaite

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

All properties

Chemical formula: CaCO₃·6H₂O
Mohs hardness: 2.5
Density: 2.23 g/cm³
Colors: Colorless White Gray Yellowish
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Pseudomorphs, Bladed Crystals, Tabular
Cleavage: Perfect
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Cold Marine Sediments, Polar Permafrost Regions
Typical price: $50-300 per specimen (rarely available to private collectors)

Where rockhounds find ikaite

Classic worldwide localities

Ika Fjord, Greenland
Bransfield Strait, Antarctica
Siberian shelf, Russia
Various cold-seep marine environments

Field-hunting tip

Look in cold marine sediments, polar permafrost regions country — that is the host setting where ikaite typically forms. If you start seeing calcite, vaterite, aragonite in float, you are in the right ground. Field specimens usually show a pseudomorphs, bladed crystals, tabular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ikaite?+

Mohs hardness is 2.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, gray, yellowish.

Where is ikaite found?+

Notable localities include Ika Fjord, Greenland; Bransfield Strait, Antarctica; Siberian shelf, Russia; Various cold-seep marine environments.

How much is ikaite worth?+

Typical asking prices fall in the range of $50-300 per specimen (rarely available to private collectors). Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like ikaite?+

Ikaite is most often confused with Calcite, Monohydrocalcite, Vaterite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with ikaite?+

Ikaite commonly co-occurs with Calcite, Vaterite, Aragonite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ikaite form in?+

Ikaite typically forms in cold marine sediments, polar permafrost regions. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ikaite used for?+

Ikaite is used in collector, scientific research.

Find ikaite on the map

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