Gehlenite is a member of the melilite group that typically forms in contact metamorphosed limestones. Collectors should look for short, prismatic, or tabular tetragonal crystals embedded within skarn mineral assemblages.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineraluncommonMelilite Group family

Gehlenite

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this gehlenite?

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 gehlenite with a known reference. Gehlenite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Gehlenite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Gehlenite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: gray, yellowish-brown, white, colorless, greenish.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: short prismatic crystals, tabular, massive.

Often confused with

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

Often found alongside gehlenite

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

All properties

Chemical formula: Ca₂Al(AlSiO₇)
Mohs hardness: 5.5-6
Density: 3.0 g/cm³
Colors: Gray Yellowish-brown White Colorless Greenish
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Short Prismatic Crystals, Tabular, Massive
Cleavage: Distinct Basal
Rarity: Uncommon
Uses: Collector, Scientific Research
Host rock: Contact Metamorphosed Limestone
Typical price: $15-100 per specimen

Where rockhounds find gehlenite

Classic worldwide localities

Monzoni Mountains, Italy
Velardena, Mexico
Franklin, New Jersey, USA
Dognecea, Romania
Kola Peninsula, Russia

Field-hunting tip

Look in contact metamorphosed limestone country — that is the host setting where gehlenite typically forms. If you start seeing calcite, diopside, wollastonite in float, you are in the right ground. Field specimens usually show a short prismatic crystals, tabular, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gehlenite?+

Mohs hardness is 5.5-6. It typically shows a vitreous luster. The streak is white. Common colors include gray, yellowish-brown, white, colorless.

Where is gehlenite found?+

Notable localities include Monzoni Mountains, Italy; Velardena, Mexico; Franklin, New Jersey, USA; Dognecea, Romania; Kola Peninsula, Russia.

How much is gehlenite worth?+

Typical asking prices fall in the range of $15-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like gehlenite?+

Gehlenite is most often confused with Vesuvianite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with gehlenite?+

Gehlenite commonly co-occurs with Calcite, Diopside, Wollastonite, Grossular, Vesuvianite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gehlenite form in?+

Gehlenite typically forms in contact metamorphosed limestone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gehlenite used for?+

Gehlenite is used in collector, scientific research.

Find gehlenite on the map

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