Heulandite-Sr is a rare member of the zeolite group characterized by its strontium dominance. It is most easily identified by its distinctive coffin-shaped tabular crystals typically found in basaltic cavities and amygdules.

Hardness

3-3.5

Mohs

Luster

Vitreous to pearly

Streak

White

Transparency

Transparent

mineralrareHeulandite Subgroup family

Heulandite-Sr

Hardness: 3-3.5
Luster: Vitreous to pearly
Streak: White
Transparency: Transparent

No image

Is this heulandite-sr?

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 heulandite-sr with a known reference. Heulandite-Sr sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to pearly.
4
Match the color range
Compare against the expected color range: white, reddish white, grayish white, brownish white, yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: crystalline, tabular.

Often confused with

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

Often found alongside heulandite-sr

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

All properties

Chemical formula: (Sr,Ca,Na)₅(Si₂₇Al₉)O₇₂·24H₂O
Mohs hardness: 3-3.5
Density: 2.2 g/cm³
Colors: White Reddish white Grayish white Brownish white Yellow
Streak: White
Luster: Vitreous to pearly
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Crystalline, tabular
Cleavage: Perfect on {010}
Rarity: Rare
Uses: Collector
Host rock: Low temperature zeolite found in a wide variety of geologic environments: volcanic rocks, metamorphic rocks, pegmatites, tuffs, and deep-sea sediments

Where rockhounds find heulandite-sr

Classic worldwide localities

Campegli, eastern Ligurian ophiolites, Italy (type locality)

Field-hunting tip

Where it forms: Low temperature zeolite found in a wide variety of geologic environments: volcanic rocks, metamorphic rocks, pegmatites, tuffs, and deep-sea sediments. If you start seeing calcite, analcime, quartz in float, you are in the right ground. Typical habit: crystalline, tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify heulandite-sr?+

Mohs hardness is 3-3.5. Luster: vitreous to pearly. The streak is white. Common colors include white, reddish white, grayish white, brownish white.

Where is heulandite-sr found?+

Notable localities include Campegli, eastern Ligurian ophiolites, Italy (type locality).

What rocks look like heulandite-sr?+

Heulandite-Sr is most often confused with Stilbite, Heulandite-Ca. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with heulandite-sr?+

Heulandite-Sr commonly co-occurs with Calcite, Analcime, Quartz, Mesolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does heulandite-sr form in?+

Where it forms: Low temperature zeolite found in a wide variety of geologic environments: volcanic rocks, metamorphic rocks, pegmatites, tuffs, and deep-sea sediments. Working float back to the host body is the standard way to chase a fresh occurrence.

What is heulandite-sr used for?+

Heulandite-Sr is used in collector.

Find heulandite-sr on the map

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