These specimens from the Siglo XX Mine present defined, brilliant, translucent and light orange colour monazite-(Ce) crystals. They are accompanied by hyaline quartz and black-brown cassiterite on matrix. Some are twinned. Monazite is found in small quantities in this mine.
Monazite gets its name from the Greek word μουάζω "monazein" meaning "to be alone," alluding to its isolated crystals and their rarity when they were first found. Monazite is generally found in granitic pegmatites, but these crystals are found in hydrothermal veins with tin and the absence of thorium (generally an accompanying element of monazite).

Size: 7.7 x 5.5 x 4.9 cm.
Main crystal: 3.5 mm.

Col J. Viñals. Col. E. Nicolau (Barcelona).

Very interesting specimen formed by a matrix of native copper crystals, partially covered by numerous red to almost black cuprite crystals, very defined and brilliant. It is accompanied in the matrix by delafossite (CuFeO2) aggregates, such as needles and radiated globules. Representative for the species. With the handwritten label of J. Viñals.

Size: 7.4 x 4.6 x 3.5 cm.
Found in ±1990.

Col J. Viñals. Col. E. Nicolau (Barcelona).

Group of twinned prismatic scolecite crystals, very brilliant and transparent. It is accompanied by small hyaline crystals of fluorapophyllite-(K), bright and very defined. Scolecite is a rather rare species of the zeolite group from India. With handwritten label by J. Viñals and belonged to the Nicolau collection (Barcelona).

Size: 8.2 x 2.6 x 2 cm.

Col J. Viñals. Col. E. Nicolau (Barcelona).

Excellent specimen formed by numerous colorless acicular crystals of bultfonteinite, a rare hydrated calcium fluorosilicate, which is accompanied by beige prismatic crystals of olmiite, a hydroxysilicate of calcium and manganese. The specimen is very representative of these species. This is the type locality for olmiite. We include pooldervaartite because it is very common since it forms a series with olmiite.

Size: 7.2 x 5.7 x 4.9 cm.

Col. E. Nicolau (Barcelona).
Type Locality

Group of prismatic celestine crystals, of very good size and from a classic Spanish locality for the species. It occurs in crystals defined by orthorhombic prisms of different orders. Translucent, brilliant and with a soft bluish tone. It belongs from the E. Nicolau collection (Barcelona), labeled by J. Viñals.

Size: 5.8 x 6 x 4.2 cm.
Main crystal: 24 x 12 mm.

Col J. Viñals. Col. E. Nicolau (Barcelona).

Rich group of prismatic crystals of gaudefroyite, a rare calcium and manganese borate-carbonate, with an intense black color. They are accompanied by brilliant hematite crystals, along with barite, calcite and orange andradite.

Size: 7.3 x 5.5 x 4.5 cm.

Col. M. Ecker (Deutchland). Col. E. Nicolau (Barcelona).
Classic locality

A sharp crystal of lazurite, sitting right up on the marble matrix. A representative miniature for this species. Lazurite is the blue component of the 'gemstone' (or, more usually, decorative rock) Lapis Lazuli, which is a lazurite-calcite-pyrite rock that has been mined as a gem material for some 9,000 years. Before the 2021 redefinition, all lazurites were only sulfide-rich varieties of haüyne and not a separate species.

Size: 6.5 x 4.7 x 4 cm.
Main crystal: 12 x 9.5 mm

This specimen is totally different from those that we usually see in the market of this Moroccan locality. The matrix is a group of quartz crystals, with a soft amethyst tone, and partially covered with chalcedony, in tiny, shiny crystals. On this matrix there is a large group of goethite crystals, lanceolate, dark brown in color and also covered with chalcedony. But millimeter quartz crystals stand out above them, most of them doubly terminated. I had never seen specimens that looked like this. Very interesting.

Size: 9.6 x 6.5 x 4 cm.

A great sample of arsenopyrite, pale gold to silver in colour with slight iridenscence and a bright metallic lustre, with several intergrown crystals all showing complex striations and serated crystal edges. Accompanied by black ferberite. Good sized and fine specimen.

Size: 8.5 x 8 x 5.5 cm.
Main crystal: 2.5 x 2.2 cm.

Group of tabular crystals of calcite of hexagonal shape, with color zoning and small recrystallizations of the same calcite in some areas of the piece. Crystals are on a matrix with fluorite, quartz and small pyrite crystals. It shows a intense reddish tone under UV light. Aesthetic specimen from this classic Moroccan locality.

Size: 8.9 x 6.5 x 6 cm.
Main crystal: 20 mm.

Fluorescent under long wave UV

A very attractive large specimen of beautiful "star" muscovite mica from Linópolis. These specimens are some of the most distinctive and eye-catching pieces of mica from any locality for their wonderful morphology. This piece has a full coverage of lovely golden-yellow color, incredibly well-formed, star shaped twinned crystals of muscovite on quartz matrix.

Size: 8.5 x 7.5 x 5.8 xm.
Main crystal: 15 mm. star

This specimen presents a good-sized anatase crystal and belongs from this unusual locality in Cáceres. It shows very defined tetragonal dipyramid shapes, with striated faces. Intense toasted honey color, translucent to opaque and shiny. It is accompanied by quartz crystals, on matrix.

Size: 9.3 x 5.5 x 5.4 cm.
Main crystal: 5 mm.

Col. E. Nicolau (Barcelona).

Without a doubt these are the best specimens of romanechite that have ever been found in Spain. These are botryoidal romanechite aggregates, shiny and very aesthetic. We will send the analysis to the buyer.

Size: 12.5 x 6.8 x 2.7 cm.
Main crystal: 2 cm.
Found in ±2016.

Classic locality

Aesthetic group of topaz crystals aesthetically disposed on a rhyolite matrix. Some of them isolated and very rich in faces. They show very well defined faces and edges, with an excellent transparency and a uniform tone. From a classic locality.

Size: 7.2 x 5.4 x 2.4 cm.
Main crystal: 12 mm.

Classic locality

A defined fluorite cubic aggregate, echeloned growths with absolutely striking green and purple phantoms inside the otherwise glassy crystals. Cubes are lustrous on all sides and free of any considerable damage. The interior is quite fascinating as is characteristic for the Okorusu Mine. This cluster of fluorite is very aesthetic and typical for the locale.

Size: 8.9 x 6.8 x 4 cm.
Main crystal: 3.5 x 3 cm.

Highly lustrous, rounded faces, jet-black spinel octahedrons included in a calcite matrix from this less well-known locality. Crystals of this size and quality are rare from here and this is a fine and good sized specimen from the E. Nicolau (Barcelona) Collection.

Size: 7.7 x 5.7 x 3 cm.
Main crystal: 1 cm.

Col. E. Nicolau (Barcelona).

Interesting specimen due to the town where it comes from. It is a druse (both sides) of small, brilliant jarosite crystals from this small ballast quarry for railway tracks, located in the area known as "La Corraliza" to the NNE of the town of Vall d'Uixó. With old label from J. Viñals.

Size: 5.8 x 4.4 x 0.8 cm.

Aggregate of brilliant, little reddish, fragmented dufrénoysite crystals. They are arranged in a cavity of the dolomite matrix, along with pyrite. Dufrénoysite belongs to the sartorite group and has a Lengenbach type locality.

Size: 7.3 x 5.1 x 4 cm.
Main crystal: 6 mm.

Type Locality

This specimen belongs from a very rare location from an active quarry in Northern Ireland. It consists of a druse of white analcime with minor amounts of basalt as a matrix. Very unusual in the market. With an old label from Mikon.

Size: 5.9 x 4.4 x 4 cm.
Main crystal: 8 mm.

Col. E. Nicolau (Barcelona).

Globular aggregates of prismatic baryte crystals, bright, defined, translucent and with a whitish color. A classic of Murcian mining.

Size: 6.6 x 3.7 x 5.2 cm.
Main crystal: 8 x 7 mm.

Group of gypsum crystals, in parallel growth, with siderite inclusions. Open pit exploitation (corta) located next to the San Valentín corta. It belongs from the collection of Joan Astor.

Size: 11.3 x 4.7 x 3.2 cm.
Found in ±1977.

Col. Joan Astor (Barcelona).

In this specimen we can observe several cubic galena crystals, very brilliant and defined, with faces of the cube truncated by the octahedron. They are accompanied by complex sphalerite spinel twin crystals. Disposed on a matrix with quartz and lenticular calcite crystals.

Size: 8.6 x 7.3 x 4.5 cm.
Main crystal: 16 x 14 mm. galena.

Scalenohedral rhodo crystals with a whitish patina. They are accompanied by very brilliant hyaline quartz crystals.

Size: 4.8 x 4 x 3.1 cm.
Main crystal: 6 mm.

Group of cubic fluorite crystals, with transparence that allows us to see the inner violet geometric zoning. Polysynthetic growths on faces. In matrix with baryte.

Size: 5.7 x 4.7 x 3.7 cm.
Main crystal: 16 mm.

Classic locality

n this specimen of chalcedony we can observe, when light passes through it, the presence of a cavity partially filled with water of crystallization. This water was trapped in the process of formation of the geode, millions of years ago. A mineralogical curiosity.

Size: 6.2 x 3.8 x 3.2 cm.