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.
Is this ikaite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch ikaite with a known reference. Ikaite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: earthy.
- 4Match the color rangeCompare against the expected color range: chalky white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: stalactitic, 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
- 1.77 g/cm³
- Colors
- Chalky white
- Streak
- White
- Luster
- Earthy
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Stalactitic, tabular
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Forms in sea water and lake water in anerobic, organic-rich periglacial and glaciomarine environments near 0°C, readily converting to calcite at higher temperatures
Where rockhounds find ikaite
Classic worldwide localities
- Seasonally at the tufa mounds of Mono Lake, Mono Co., California, USA
- Waters of the Ika Fjord, eight km south of Ivigtut, Greenland
- Sub-bottom sediment, Bransfield Strait, King George Basin, Antarctica
- Zaire deep-sea fan, Atlantic Ocean
- Sediments of the Nankai Trough, south of Japan
Field-hunting tip
Where it forms: Forms in sea water and lake water in anerobic, organic-rich periglacial and glaciomarine environments near 0°C, readily converting to calcite at higher temperatures. If you start seeing calcite, vaterite, aragonite in float, you are in the right ground. Typical habit: stalactitic, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ikaite?+
Where is ikaite found?+
What rocks look like ikaite?+
What minerals are found with ikaite?+
What kind of rock does ikaite form in?+
What is ikaite used for?+
Find ikaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
