Retzian-(La) is an extremely rare arsenate mineral member of the retzian group. It is primarily found in the metamorphosed manganese mines of Sweden as small, reddish-brown crystals, and it requires advanced analytical methods for positive identification due to its similarity to other members of the group.

Hardness

3-4

Mohs

Luster

Vitreous on {010} and fractures, otherwise dull

Streak

Pale brown

Transparency

Transparent

mineralrareRetzian Group family

Retzian-(La)

Hardness: 3-4
Luster: Vitreous on {010} and fractures, otherwise dull
Streak: Pale brown
Transparency: Transparent

No image

Is this retzian-(la)?

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 retzian-(la) with a known reference. Retzian-(La) sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pale brown.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous on {010} and fractures, otherwise dull.
4
Match the color range
Compare against the expected color range: reddish brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, granular masses.

Often confused with

Retzian-(La) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Retzian-(La) leaves pale brown, Retzian-(Nd) leaves very pale brown.

Often found alongside retzian-(la)

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

All properties

Chemical formula: Mn₂LaAsO₄(OH)₄
Mohs hardness: 3-4
Density: 4.49 g/cm³
Colors: Reddish brown
Streak: Pale brown
Luster: Vitreous on {010} and fractures, otherwise dull
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals, granular masses
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A very rare late phase in fractures in a metamorphosed stratiform zinc orebody

Where rockhounds find retzian-(la)

Classic worldwide localities

Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA

Field-hunting tip

Where it forms: A very rare late phase in fractures in a metamorphosed stratiform zinc orebody. If you start seeing willemite, franklinite, calcite in float, you are in the right ground. Typical habit: tabular crystals, granular masses. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify retzian-(la)?+

Mohs hardness is 3-4. Luster: vitreous on {010} and fractures, otherwise dull. The streak is pale brown. Common colors include reddish brown.

Where is retzian-(la) found?+

Notable localities include Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA.

Is retzian-(la) safe to handle?+

Retzian-(La) contains arsenic and calls for real care. Contains arsenic, which is toxic. Handle with care, wash hands after touching, and do not ingest or inhale dust.

What rocks look like retzian-(la)?+

Retzian-(La) is most often confused with Retzian-(Nd), Retzian-(Ce). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with retzian-(la)?+

Retzian-(La) commonly co-occurs with Willemite, Franklinite, Calcite, Todorokite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does retzian-(la) form in?+

Where it forms: A very rare late phase in fractures in a metamorphosed stratiform zinc orebody. Working float back to the host body is the standard way to chase a fresh occurrence.

What is retzian-(la) used for?+

Retzian-(La) is used in collector.

Find retzian-(la) on the map

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