CUCA FRONT — Exclusive Reopening 2026

Ambas Aguas, La Rioja, Spain

“Once sealed beneath time and saltwater, the Cuca Front awakens again — for a chosen few.”

For the first time since the 1990s, the legendary Cuca Front of Ambas Aguas will reopen. Hidden deep within the Barranco de Aguasala, this is the farthest and most demanding front of the mine — where black lutites, saltwater springs, and hydroplastic fractures forged some of the most coveted pyrite ever discovered.

The Cuca specimens are unmistakable: jet-black matrices hosting massive, striated cubes and pyritohedra, often in sculptural clusters exceeding 10 cm, each crystal marked by fragments of its native shale. These are specimens of legend — many long since locked in private collections, unseen since the old collectors of the 1990s. No modern photographs exist; permission for reproduction has been refused by their owners. Since the publication of García & Alonso-Azcárate (1997), a handful of new crystallizations have appeared — all kept hidden.

Now, in 2026, the Cuca Front will reopen only once, for a small group of selected visitors. After this window, it will again be sealed indefinitely.

About the Cuca Front

Situated at the junction of the Muro de Aguas path and the Arroyo de las Cañadillas, Cuca’s mineralization emerges within black lutites enriched by saline groundwater. The pyrite formed in deltaic carbonate-lake sediments, shaped by hydroplastic fractures (“lisos”) that allowed perfect crystal development and effortless separation. These planes yield the front’s signature contrast — deep black matrix against intensely striated golden faces — a union of earth and geometry rarely seen elsewhere.

2026 Extraction Program

Participation: By invitation or accepted application only
Assisted Extraction Duration: 4 hours
Extraction Window: Mid-March – Mid-October
(excluding Sainte-Marie-aux-Mines show period)
Contribution: €15 000
Payment: Due within 15 days of acceptance

Extraction Value Threshold

To preserve both rarity and integrity, total recovered specimen value per participant is capped at €75 000 (market-estimated specimen value) or until the allotted extraction time limit is reached — whichever comes first.
Once either threshold is achieved, extraction must cease. This ensures the legacy of the front and maintains the exclusivity of each recovered specimen.

“This is not an ordinary dig — it is an initiation.”
Participation is restricted to those who understand that access to beauty carries responsibility.

Interested collectors or institutions may submit an Application for Cuca Front Access to:
📩 piritas.ambasaguas@gmail.com

Applications should include a short statement of interest and relevant mineralogical background.
Approved applicants will receive full logistics and safety documentation under confidentiality.