TERRIUM — A mineralogy cabinet

Todorokita

Todorokita is a mineral with formula (Na,Ca,K,Ba,Sr)₁₋ₓ(Mn²⁺,Mn⁴⁺)₆O₁₂·3-4H₂O, in the Óxidos group. This specimen comes from Mina El Conjuro, Busquístar, Granada, Andalucía, España and joined the Terrium collection in 2025.

Todorokita from Mina El Conjuro, Busquístar, Granada, Andalucía, España — Terrium

Description

Silvery metallic fibrous crystals, standing upright within a deep geode. The contrast with the matte-black interior and limonitic rims gives the piece an almost sculptural aspect.

History of this specimen

The original owner thought it was native silver because of its colour and shape, and sent it to Germany for analysis. The result confirmed it is todorokite, a rare mineral that occurs in cavities of manganese oxides and is little known in Spain. It features on FMF https://www.foro-minerales.com/forum/download.php?id=10664

About Todorokita

Todorokite is a complex hydrated manganese oxide incorporating elements such as sodium, calcium and barium. It forms at low temperatures and may occur in both hydrothermal environments and marine nodules.

About the locality

El Conjuro mine, in Busquístar, Granada, forms part of the Sierra Nevada mining district. It produced manganese oxides, and its cavities with secondary mineralisation were especially valued. Now closed, it has been studied for its rare species and geochemical complexity.

Technical data

Catalogue No.
0344
Internal reference
T0012
Composition
(Na,Ca,K,Ba,Sr)₁₋ₓ(Mn²⁺,Mn⁴⁺)₆O₁₂·3-4H₂O
Name
Todorokita
Group
Óxidos
Category
Cavella
Matrix
Goethita masiva y limonita
Mine
Mina El Conjuro
District / Municipality
Busquístar
Province
Granada
Region
Andalucía
Country
España
Size (cm)
5.5 x 5 x 2
Weight
80 g
Acquired
2025
Etymology
rom the Todoroki Mine (Japan), the place where it was discovered in 1934. In Japanese, the word means roar or rumble.
Quality
Buena
Value trend
Estable

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