Galliskiite is an extremely rare phosphate mineral discovered in complex granite pegmatites. It typically forms as small, colorless to white tabular crystals and is primarily sought after by advanced systematic mineral collectors.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Galliskiite

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

No image

Is this galliskiite?

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 galliskiite with a known reference. Galliskiite 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. Galliskiite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Galliskiite 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: tabular crystals.

Often confused with

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

mineral

Wardite

Mohs 5

How to tell apart: Wardite is the harder of the two (Mohs 5 vs. 3.5).

Often found alongside galliskiite

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

All properties

Chemical formula: Ca₄Al₂F₈(PO₄)₂·5H₂O
Mohs hardness: 3.5
Density: 2.88 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $100-500+ per specimen

Where rockhounds find galliskiite

Classic worldwide localities

Argentina

Field-hunting tip

Look in granite pegmatites country — that is the host setting where galliskiite typically forms. If you start seeing wardite, englishite, apatite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify galliskiite?+

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

Where is galliskiite found?+

Notable localities include Argentina.

How much is galliskiite worth?+

Typical asking prices fall in the range of $100-500+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like galliskiite?+

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

What minerals are found with galliskiite?+

Galliskiite commonly co-occurs with Wardite, Englishite, Apatite, Siderite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does galliskiite form in?+

Galliskiite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is galliskiite used for?+

Galliskiite is used in collector.

Find galliskiite on the map

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