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, 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.