Yeatmanite is a rare manganese zinc silicate-antimonate mineral found primarily in the famous Franklin District of New Jersey. It typically occurs as reddish-brown tabular crystals or granular masses associated with other rare zinc-manganese species in metamorphic limestone.
Is this yeatmanite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch yeatmanite with a known reference. Yeatmanite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very light brown.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: clove brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: anhedral grains, platy.
Often confused with
Yeatmanite 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. 4); streak differs, so Yeatmanite leaves very light brown, Willemite leaves white.
How to tell apart: Franklinite is the harder of the two (Mohs ~6 vs. 4); streak differs, so Yeatmanite leaves very light brown, Franklinite leaves reddish brown to black; luster reads vitreous on Yeatmanite and metallic to semimetallic; may be dull on Franklinite.
Often found alongside yeatmanite
Minerals reported to co-occur with yeatmanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn,Zn)₁₆Sb₂Si₄O₂₈
- Mohs hardness
- 4
- Density
- 5.02 g/cm³
- Colors
- Clove brown
- Streak
- Very light brown
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Anhedral grains, platy
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In veins in massive granular ore in a metamorphosed stratiform zinc deposit
Where rockhounds find yeatmanite
Classic worldwide localities
- Franklin, Sussex Co., New Jersey, USA
Field-hunting tip
Where it forms: In veins in massive granular ore in a metamorphosed stratiform zinc deposit. If you start seeing sarkinite, willemite, calcite in float, you are in the right ground. Typical habit: anhedral grains, platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yeatmanite?+
Where is yeatmanite found?+
Is yeatmanite safe to handle?+
What rocks look like yeatmanite?+
What minerals are found with yeatmanite?+
What kind of rock does yeatmanite form in?+
What is yeatmanite used for?+
Find yeatmanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
