Magadiite is a rare layered silicate mineral primarily found in hypersaline, alkaline lake environments like the Lake Magadi basin. It typically forms delicate white, platy, or rosette-like crystal aggregates that can be visually distinguished by their association with evaporite minerals.

Hardness

Mohs

Luster

Vitreous to dull

Streak

White

Transparency

Translucent to opaque

mineralrare

Magadiite

Hardness: 2
Luster: Vitreous to dull
Streak: White
Transparency: Translucent to opaque

Is this magadiite?

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 magadiite with a known reference. Magadiite sits at Mohs 2, 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 to dull.
4
Match the color range
Compare against the expected color range: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: microscopic crystals, platy, powdery.

Often confused with

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

How to tell apart: Luster reads vitreous to dull on Magadiite and pearly on Kenyaite.

How to tell apart: Kanemite is the harder of the two (Mohs ~4 vs. 2); luster reads vitreous to dull on Magadiite and silky on Kanemite.

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Often found alongside magadiite

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

All properties

Chemical formula: NaSi₇O₁₃(OH)₃·3H₂O
Mohs hardness: 2
Density: 2.25 g/cm³
Colors: White
Streak: White
Luster: Vitreous to dull
Transparency: Translucent to opaque
Crystal system: Monoclinic
Crystal habit: Microscopic crystals, platy, powdery
Cleavage: Perfect
Fluorescence: Yellow-white under SW and LW UV
Rarity: Rare
Uses: Collector
Host rock: In silts of upper Pleistocene to recent age, precipitated by evaporation of saline brines (Lake Magadi, Kenya)

Where rockhounds find magadiite

Classic worldwide localities

Alkali Lake Playa, Lake Co., Oregon, and about five km north of Trinity Lake, Trinity Co., California, USA
Lake Magadi and Lake Bogoria, Rift Valley, Kenya
Kanem area, Lake Chad, Chad
Mont Saint-Hilaire and near Saint-Amable, Quebec, Canada

Field-hunting tip

Where it forms: In silts of upper Pleistocene to recent age, precipitated by evaporation of saline brines (Lake Magadi, Kenya). If you start seeing kenyaite, calcite, kanemite in float, you are in the right ground. Typical habit: microscopic crystals, platy, powdery. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify magadiite?+

Mohs hardness is 2. Luster: vitreous to dull. The streak is white. Common colors include white.

Where is magadiite found?+

Notable localities include Alkali Lake Playa, Lake Co., Oregon, and about five km north of Trinity Lake, Trinity Co., California, USA; Lake Magadi and Lake Bogoria, Rift Valley, Kenya; Kanem area, Lake Chad, Chad; Mont Saint-Hilaire and near Saint-Amable, Quebec, Canada.

What rocks look like magadiite?+

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

What minerals are found with magadiite?+

Magadiite commonly co-occurs with Kenyaite, Calcite, Kanemite, Bavenite, Pectolite, Apophyllite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does magadiite form in?+

Where it forms: In silts of upper Pleistocene to recent age, precipitated by evaporation of saline brines (Lake Magadi, Kenya). Working float back to the host body is the standard way to chase a fresh occurrence.

What is magadiite used for?+

Magadiite is used in collector.

Find magadiite on the map

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