Spadaite is a rare, hydrated magnesium silicate that typically appears in massive, waxy, or compact forms. It is most commonly found in cavities within igneous rocks or associated with serpentine and hydrothermal deposits.

Hardness

2.5

Mohs

Luster

Pearly or greasy

Streak

White

Transparency

Translucent

mineralrareSepiolite Group family

Spadaite

Hardness: 2.5
Luster: Pearly or greasy
Streak: White
Transparency: Translucent

Is this spadaite?

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 spadaite with a known reference. Spadaite 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: pearly or greasy.
4
Match the color range
Compare against the expected color range: colorless, cream, pinkish.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: amorphous, massive.

Often confused with

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

mineral

Sepiolite

Mohs 2-2.5

How to tell apart: Luster reads pearly or greasy on Spadaite and dull on Sepiolite.

Often found alongside spadaite

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

All properties

Chemical formula: MgSiO₃·nH₂O
Mohs hardness: 2.5
Density: 2.2 g/cm³
Colors: Colorless Cream Pinkish
Streak: White
Luster: Pearly or greasy
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Amorphous, massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In leucite-bearing lava (Capo di Bove, Italy); in amygdular diabase (Sasbach, Germany); replacing tactite minerals near gold ore shoots (Gold Hill, Utah, USA)

Where rockhounds find spadaite

Classic worldwide localities

Cane Springs, Alvarado, and Midas mines, near Gold Hill, Tooele Co., Utah, and in the Livingston quarry, Palos Verdes Hills, Los Angeles Co., California, USA
Capo di Bove, near Rome, Lazio, Italy
Sasbach, Baden-Württemberg, Germany

Field-hunting tip

Where it forms: In leucite-bearing lava (Capo di Bove, Italy); in amygdular diabase (Sasbach, Germany); replacing tactite minerals near gold ore shoots (Gold Hill, Utah, USA). If you start seeing wollastonite, diopside, garnet in float, you are in the right ground. Typical habit: amorphous, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify spadaite?+

Mohs hardness is 2.5. Luster: pearly or greasy. The streak is white. Common colors include colorless, cream, pinkish.

Where is spadaite found?+

Notable localities include Cane Springs, Alvarado, and Midas mines, near Gold Hill, Tooele Co., Utah, and in the Livingston quarry, Palos Verdes Hills, Los Angeles Co., California, USA; Capo di Bove, near Rome, Lazio, Italy; Sasbach, Baden-Württemberg, Germany.

What rocks look like spadaite?+

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

What minerals are found with spadaite?+

Spadaite commonly co-occurs with Wollastonite, Diopside, Garnet. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does spadaite form in?+

Where it forms: In leucite-bearing lava (Capo di Bove, Italy); in amygdular diabase (Sasbach, Germany); replacing tactite minerals near gold ore shoots (Gold Hill, Utah, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is spadaite used for?+

Spadaite is used in collector.

Find spadaite on the map

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