Gowerite is a rare calcium borate mineral that typically forms as delicate, radial aggregates or bladed crystals. It is primarily identified within borate-rich sedimentary deposits and is a prized find for advanced mineral collectors focusing on evaporite species.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareBorate Group family

Gowerite

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

Is this gowerite?

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 gowerite with a known reference. Gowerite sits at Mohs 3, 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: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: bladed crystals, radial aggregates, spherulitic.

Often confused with

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

mineral

Colemanite

Mohs 4.5

How to tell apart: Colemanite is the harder of the two (Mohs 4.5 vs. 3).

Often found alongside gowerite

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

All properties

Chemical formula: Ca[B₅O₈(OH)][B(OH)₃]·3H₂O
Mohs hardness: 3
Density: 2.00 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Bladed crystals, radial aggregates, spherulitic
Cleavage: {001}, distinct; {100}, imperfect
Fluorescence: Weak blue white under SW and LW UV
Rarity: Rare
Uses: Collector
Host rock: A rare weathering product of colemanite and priceite

Where rockhounds find gowerite

Classic worldwide localities

Mott open cut, head of 20 mule Team Canyon, Death Valley, Inyo Co. California (type locality)

Field-hunting tip

Where it forms: A rare weathering product of colemanite and priceite. If you start seeing meyerhofferite, nobleite, hydroboracite in float, you are in the right ground. Typical habit: bladed crystals, radial aggregates, spherulitic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gowerite?+

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

Where is gowerite found?+

Notable localities include Mott open cut, head of 20 mule Team Canyon, Death Valley, Inyo Co. California (type locality).

What rocks look like gowerite?+

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

What minerals are found with gowerite?+

Gowerite commonly co-occurs with Meyerhofferite, Nobleite, Hydroboracite, Ulexite, Ginorite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gowerite form in?+

Where it forms: A rare weathering product of colemanite and priceite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gowerite used for?+

Gowerite is used in collector.

Find gowerite on the map

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