Inderborite is a rare hydrated calcium magnesium borate mineral typically found in evaporite basins. Collectors should look for its characteristic prismatic, often colorless to white crystals that usually form within salt lake deposits or salt domes.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareBorate Group family

Inderborite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this inderborite?

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 inderborite with a known reference. Inderborite sits at Mohs 3.5, 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, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates.

Often confused with

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

How to tell apart: Preobrazhenskite is the harder of the two (Mohs 4.5-5 vs. 3.5); luster reads vitreous on Inderborite and pearly on Preobrazhenskite.

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Often found alongside inderborite

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

All properties

Chemical formula: CaMg[B₃O₃(OH)₅]₂·6H₂O
Mohs hardness: 3.5
Density: 1.93-2.00 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Prismatic crystals, radial aggregates
Cleavage: On {100}, good
Rarity: Rare
Uses: Collector
Host rock: With other borates in the caprock of a salt diapir (Inder deposit, Kazakhstan); in lacustrine borate deposits (Sarıkaya, Turkey)

Where rockhounds find inderborite

Classic worldwide localities

Furnace Creek district, Death Valley, Inyo Co., California, USA
Der borate deposit, Kazakhstan
Sarıkaya, near Kirka, Eskiçehir Province, Turkey
Günevi mine, Bigadiç borate district, Balıkesir Province, Turkey
Santa Rosa mine, Sijes district, Salta Province, Argentina

Field-hunting tip

Where it forms: With other borates in the caprock of a salt diapir (Inder deposit, Kazakhstan); in lacustrine borate deposits (Sarıkaya, Turkey). If you start seeing inyoite, colemanite, ulexite in float, you are in the right ground. Typical habit: prismatic crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify inderborite?+

Mohs hardness is 3.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is inderborite found?+

Notable localities include Furnace Creek district, Death Valley, Inyo Co., California, USA; Der borate deposit, Kazakhstan; Sarıkaya, near Kirka, Eskiçehir Province, Turkey; Günevi mine, Bigadiç borate district, Balıkesir Province, Turkey; Santa Rosa mine, Sijes district, Salta Province, Argentina.

What rocks look like inderborite?+

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

What minerals are found with inderborite?+

Inderborite commonly co-occurs with Inyoite, Colemanite, Ulexite, Szaibélyite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does inderborite form in?+

Where it forms: With other borates in the caprock of a salt diapir (Inder deposit, Kazakhstan); in lacustrine borate deposits (Sarıkaya, Turkey). Working float back to the host body is the standard way to chase a fresh occurrence.

What is inderborite used for?+

Inderborite is used in collector.

Find inderborite on the map

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