Strengite is an attractive iron phosphate mineral often sought by collectors for its vibrant violet to raspberry-red colors. It typically forms as radiating spherical, botryoidal, or drusy aggregates, and is commonly found in the oxidized zones of iron-rich mineral deposits.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineraluncommon

Strengite

Hardness: 3.5-4
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this strengite?

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 strengite with a known reference. Strengite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Strengite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Strengite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: red, violet, pink, magenta, colorless.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: botryoidal, crusts, radial aggregates, or prismatic crystals.

Often confused with

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

mineral

Variscite

Mohs 3.5-4.5

How to tell apart: Luster reads vitreous on Strengite and waxy on Variscite.

Often found alongside strengite

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

All properties

Chemical formula: FePO₄·2H₂O
Mohs hardness: 3.5-4
Density: 2.87 g/cm³
Colors: Red Violet Pink Magenta Colorless
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Botryoidal, Crusts, Radial Aggregates, Or Prismatic Crystals
Cleavage: Good On {010}
Rarity: Uncommon
Uses: Collector, Ornamental
Host rock: Phosphate-rich Hydrothermal Veins in Granitic Pegmatites or Secondary Gossans
Typical price: $15-150 thumbnail, $50-500 cabinet specimen

Where rockhounds find strengite

Classic worldwide localities

Pleystein, Germany
Minas Gerais, Brazil
Rockbridge County, Virginia, USA
Yukon Territory, Canada

Field-hunting tip

Look in phosphate-rich hydrothermal veins in granitic pegmatites or secondary gossans country, the host setting where strengite typically forms. If you start seeing vivianite, cacoxenite, rockbridgeite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, radial aggregates, or prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify strengite?+

Mohs hardness is 3.5-4. It typically shows a vitreous luster. The streak is white. Common colors include red, violet, pink, magenta.

Where is strengite found?+

Notable localities include Pleystein, Germany; Minas Gerais, Brazil; Rockbridge County, Virginia, USA; Yukon Territory, Canada.

How much is strengite worth?+

Typical asking prices fall in the range of $15-150 thumbnail, $50-500 cabinet specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like strengite?+

Strengite is most often confused with Variscite, Phosphosiderite, Ludlamite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with strengite?+

Strengite commonly co-occurs with Vivianite, Cacoxenite, Rockbridgeite, Leucophosphite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does strengite form in?+

Strengite typically forms in phosphate-rich hydrothermal veins in granitic pegmatites or secondary gossans. Working float back to the host body is the standard way to chase a fresh occurrence.

What is strengite used for?+

Strengite is used in collector, ornamental.

Find strengite on the map

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