Arsenoflorencite-(La) is a rare arsenic-bearing member of the alunite supergroup typically found as small rhombohedral crystals. It is a secondary mineral that occurs in weathered hydrothermal deposits and is highly sought after by systematic mineral collectors.
Is this arsenoflorencite-(la)?
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 arsenoflorencite-(la) with a known reference. Arsenoflorencite-(La) sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very pale pink.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals.
Often confused with
Arsenoflorencite-(La) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Florencite-(Ce) is the harder of the two (Mohs 5-6 vs. 3.5); streak differs, so Arsenoflorencite-(La) leaves very pale pink, Florencite-(Ce) leaves white; luster reads vitreous on Arsenoflorencite-(La) and greasy to resinous on Florencite-(Ce).
How to tell apart: Streak differs, so Arsenoflorencite-(La) leaves very pale pink, Arsenogoyazite leaves white.
Often found alongside arsenoflorencite-(la)
Minerals reported to co-occur with arsenoflorencite-(la). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- LaAl₃(AsO₄)₂(OH)₆
- Mohs hardness
- 3.5
- Density
- 4.15 g/cm³
- Colors
- Streak
- Very pale pink
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral crystals
- Cleavage
- Fair on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As zones within crystals of florencite-(Ce) and zoned crystals with ‘‘arsenoflorencite- (Nd)’’ and crandallite, in Mn-rich nodules in metasediments
Where rockhounds find arsenoflorencite-(la)
Classic worldwide localities
- Brazil
- Australia
- China
Field-hunting tip
Where it forms: As zones within crystals of florencite-(Ce) and zoned crystals with ‘‘arsenoflorencite- (Nd)’’ and crandallite, in Mn-rich nodules in metasediments. If you start seeing zircon, quartz, hematite in float, you are in the right ground. Typical habit: rhombohedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify arsenoflorencite-(la)?+
Where is arsenoflorencite-(la) found?+
Is arsenoflorencite-(la) safe to handle?+
What rocks look like arsenoflorencite-(la)?+
What minerals are found with arsenoflorencite-(la)?+
What kind of rock does arsenoflorencite-(la) form in?+
What is arsenoflorencite-(la) used for?+
Find arsenoflorencite-(la) on the map
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