Cuatrocapaite-(NH4) is a very rare ammonium copper sulfate mineral first identified in evaporite deposits in Mexico. It typically occurs as small, pale yellow, platy crystals forming in arid environments and is highly sought after by advanced mineral collectors.

Hardness
2
Mohs
Luster
Vitreous
Streak
White
Transparency
Transparent

Is this cuatrocapaite-(nh4)?

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 cuatrocapaite-(nh4) with a known reference. Cuatrocapaite-(NH4) sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Cuatrocapaite-(NH4) leaves a white streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Cuatrocapaite-(NH4) typically shows a vitreous luster.
  • 4
    Match the color range
    Compare against the expected color range: yellow, pale yellow.
  • 5
    Look at form & habit
    Crystal system: trigonal. Typical habit: platy crystals.

Often found alongside cuatrocapaite-(nh4)

Minerals reported to co-occur with cuatrocapaite-(nh4). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
(NH₄)₄Cu₂(SO₄)₃
Mohs hardness
2
Density
2.44 g/cm³
Streak
White
Luster
Vitreous
Transparency
Transparent
Crystal system
Trigonal
Crystal habit
Platy Crystals
Cleavage
Perfect
Rarity
Rare
Uses
Collector
Host rock
Evaporite Deposits
Typical price
expensive due to rarity

Where rockhounds find cuatrocapaite-(nh4)

Classic worldwide localities

  • Cuatro Cienegas, Coahuila, Mexico

Field-hunting tip

Look in evaporite deposits country — that is the host setting where cuatrocapaite-(nh4) typically forms. If you start seeing gypsum, thenardite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cuatrocapaite-(nh4)?+
Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include yellow, pale yellow.
Where is cuatrocapaite-(nh4) found?+
Notable localities include Cuatro Cienegas, Coahuila, Mexico.
How much is cuatrocapaite-(nh4) worth?+
Typical asking prices fall in the range of expensive due to rarity. Quality, size, and provenance can move individual specimens well outside that range.
What minerals are found with cuatrocapaite-(nh4)?+
Cuatrocapaite-(NH4) commonly co-occurs with gypsum, thenardite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does cuatrocapaite-(nh4) form in?+
Cuatrocapaite-(NH4) typically forms in evaporite deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is cuatrocapaite-(nh4) used for?+
Cuatrocapaite-(NH4) is used in collector.

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