Gladiusite is a rare hydrated iron phosphate mineral typically found as small, sword-like prismatic crystals. It is primarily known from the Big Fish River area of Canada, where it occurs within phosphatic iron-rich sedimentary deposits. Collectors look for its characteristic morphology and its association with other secondary phosphate minerals.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Gladiusite

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

No image

Is this gladiusite?

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 gladiusite with a known reference. Gladiusite 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. Gladiusite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Gladiusite typically shows a vitreous luster.
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.

Often confused with

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

mineral

Vivianite

Mohs 1.5-2

How to tell apart: Gladiusite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs, so Gladiusite leaves white, Vivianite leaves white to light blue.

Often found alongside gladiusite

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

All properties

Chemical formula: Fe₂⁺₂(PO₄)(OH)·H₂O
Mohs hardness: 3.5
Density: 2.95 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Sedimentary Iron Formations
Typical price: $50-300 per specimen

Where rockhounds find gladiusite

Classic worldwide localities

Big Fish River, Yukon Territory, Canada

Field-hunting tip

Look in sedimentary iron formations country, the host setting where gladiusite typically forms. If you start seeing vivianite, ludlamite, arrojadite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gladiusite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is gladiusite found?+

Notable localities include Big Fish River, Yukon Territory, Canada.

How much is gladiusite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like gladiusite?+

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

What minerals are found with gladiusite?+

Gladiusite commonly co-occurs with Vivianite, Ludlamite, Arrojadite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gladiusite form in?+

Gladiusite typically forms in sedimentary iron formations. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gladiusite used for?+

Gladiusite is used in collector.

Find gladiusite on the map

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