Sedimentary Rocks · common
Caliche
Caliche is a hardened calcium carbonate-rich soil or sediment layer, also called calcrete or hardpan, common in arid and semi-arid regions.
Also known as: Calcrete, Hardpan, Carbonate hardpan.
Caliche properties at a glance
| Type | Sedimentary Rocks |
|---|---|
| Chemical formula | Calcium carbonate-cemented sediment |
| Mohs hardness | 3 |
| Luster | dull |
| Streak | White to pale tan |
| Cleavage | Variable by mineral grains |
| Fracture | Earthy to uneven |
| Specific gravity | 2.4 |
| Transparency | opaque |
| Common colors | White, Cream, Tan, Gray, Brown |
| Rarity | common |
Geology & background
Forms in soils and near-surface sediments where calcium carbonate precipitates and cements grains into hard layers or nodules.
Caliche is useful in interpreting ancient soils, dry climates, and near-surface carbonate cementation.
How to identify Caliche
- Look for hard, pale, earthy carbonate cement in soil-like or near-surface material.
- Caliche is common in dry-region soils and may occur as nodules, crusts, or ledges.
- It may fizz with dilute acid because it contains calcium carbonate.
- Texture can include cemented sand, gravel, clay, or root-like structures.
Full Caliche identification guide: checklist, home tests and look-alikes →
Caliche vs similar stones
Not sure it isn't something else? Side-by-side comparisons with the stones most often confused with Caliche.
Where Caliche is found
Caliche occurs in many sedimentary settings worldwide; exact locality should be verified from field notes, maps, or specimen provenance.
How much is Caliche worth?
| Entry-level specimen | $1 |
|---|---|
| Typical collector specimen | $10 |
| Premium specimen | $75+ |
Caliche is usually valued for teaching, field context, locality, texture, fossils, color, or unusual structures rather than high gem value.
Common uses
- Field identification
- Education
- Paleosol study
- Local construction material in some regions
Interesting facts
- Caliche is often a soil-related carbonate deposit rather than a typical bedded marine rock.
- It can cement sand, gravel, silt, or clay into hard crusts and nodules.
- Caliche layers can record dry climate and landscape stability.
Care & safety
Caliche can be soft, porous, crumbly, or weakly cemented depending on grain size, cement, and weathering.
Avoid inhaling dust. Do not cut, grind, or polish unknown sedimentary rocks without eye protection and a properly rated respirator.
Caliche FAQ
What is Caliche?
Caliche is a hardened calcium carbonate-rich soil or sediment layer, also called calcrete or hardpan, common in arid and semi-arid regions.
How much is Caliche worth?
Entry-level Caliche specimens sell for around $1, a typical collector specimen for about $10, and premium pieces for $75 or more. Caliche is usually valued for teaching, field context, locality, texture, fossils, color, or unusual structures rather than high gem value.
How hard is Caliche?
Caliche has a Mohs hardness of 3. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
What is Caliche used for?
Caliche is used for field identification, education, paleosol study, and local construction material in some regions.
