The “mineral” richness of the Dognecea Mountains (Romania) attracted attention of the most important mineralogists of the time, being known both for richness and variety of the mining sites and for the outstanding beauty of the collected samples.

Mineralogical researches placed the Dognecea Mountains in the literature as a typical zone for studying minerals of the contact rocks and the mineralization, as a representative region.

Within this area of skarns Ocna de Fier Dognecea new minerals were found for the first time in the whole world – locus tipicus – such as: – Andradite – Ocna de Fier (1800) – Ludwigite – Ocna de Fier (1874) – Dogneceaite – Dognecea (1884) – Warthaite – Ocna de Fier (1925)

In this very zone also “rare minerals” were mentioned for the first time in Romania, such as: Paligorksite (1967), Mn-ilvaite (1968), Mn-ferosalite (1969) and Mn-salite (1974).

In 1972 at Ocna de Fier, in the Reichenstein mine, in the upper part of Delius deposit, in a geode, Constantin Gruescu discovered for the first time in the world a new shape of quartz macle (twin-crystal), the coaxial one with radial concrescences, doubly and triply macled, named now Gruescu macle.

The Japanese quartz macle described in the literature has crystals only several mm long, whereas at Ocna de Fier, as an European rarity, we can find samples with crystals several cm long.

The andradite and grossular crystals found in the geodes at Terezia quarry, Delius mines, Middle Body and Markus 40 at Ocna de Fier are mineralogical aggregates of the great variety.

Other interesting items are crystallization shapes of calcite both at Ocna de Fier, where scalenohedral shapes are predominant, and at Dognecea, where the samples lamellar-tubular shape gives them a particularly bizzare and aesthetic hue.

Iron ores like magnetite and haematite are found in crystal shapes. Haematites of Terezia quarry and Middle Body at Ocna de Fier have lamellar crystals disposed in rosettes, and the magnetite formed after the silicates composing the skarn that it substitutes has their crystallographic shape, generally the shape of a rhomboidal dodecahedron.

A particular aesthetic value is to be found with malachite, having radial crystal shape, discovered in Petru and Pavel Body at he the Reichenstein gallery level in the little geodes placed in a compact mass of hematite.

It is very difficult to comprise in a single collection the entire range of the Dognecea Mountains mineralogy, because there is such a great variety of the “minerals” and they have been exploited for many centuries; since the beginning of the mining process, the topography has been continually changing and the ground morphology has taken so many successive forms. And what’s more, by the exhaustion of some deposits because of continuous mining, the minerals of this zone disappeared in great number never to be found anymore.

Mr. Gruescu’s collection of aesthetic mineralogy of Ocna de Fier remains one of the most valuable collections, both scientifically and aesthetically. By the multitude and richness of the exhibited minerals it reconstitutes the mineralogical assets of the mountainous Banat.