Samfowlerite is a very rare silicate mineral found exclusively in the unique metamorphic environment of Franklin, New Jersey. It typically occurs as small, pale pink to colorless tabular crystals or granular masses associated with other zinc-rich minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrare

Samfowlerite

Hardness: <3
Luster: Vitreous
Streak: White
Transparency: Semitransparent

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Is this samfowlerite?

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 samfowlerite with a known reference. Samfowlerite sits at Mohs <3, 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.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: crystalline.

Often confused with

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

How to tell apart: Willemite is the harder of the two (Mohs 5.5 vs. <3).

How to tell apart: Clinohedrite is the harder of the two (Mohs 5.5 vs. <3); luster reads vitreous on Samfowlerite and brilliant, glassy; pearly on {010} on Clinohedrite.

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Often found alongside samfowlerite

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

All properties

Chemical formula: Ca₁₄Mn₃Zn₂Be₂Be₆Si₁₄O₅₂(OH)₆
Mohs hardness: <3
Density: 3.28 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Crystalline
Cleavage: None
Fluorescence: Weak red under SW and LW UV
Rarity: Rare
Uses: Collector
Host rock: In vugs in granular willemite-franklinite-andradite ore from a metamorphosed stratiform Zn{Mn deposit

Where rockhounds find samfowlerite

Classic worldwide localities

Franklin, Sussex Co., New Jersey, USA

Field-hunting tip

Where it forms: In vugs in granular willemite-franklinite-andradite ore from a metamorphosed stratiform Zn{Mn deposit. If you start seeing andradite-grossular, cahnite, clinochlore in float, you are in the right ground. Typical habit: crystalline. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify samfowlerite?+

Mohs hardness is <3. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is samfowlerite found?+

Notable localities include Franklin, Sussex Co., New Jersey, USA.

Is samfowlerite safe to handle?+

Samfowlerite contains beryllium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like samfowlerite?+

Samfowlerite is most often confused with Hardystonite, Willemite, Clinohedrite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with samfowlerite?+

Samfowlerite commonly co-occurs with Andradite-grossular, Cahnite, Clinochlore, Leucophoenicite, Johnbaumite, Barite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does samfowlerite form in?+

Where it forms: In vugs in granular willemite-franklinite-andradite ore from a metamorphosed stratiform Zn{Mn deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is samfowlerite used for?+

Samfowlerite is used in collector.

Find samfowlerite on the map

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