HomeMineralsBlogVirtual galleryAbout RMContactUser
Language
0
You are in > Home > Minerals

RM3376   Strüverite, a Ta- and Fe-bearing variety of rutile

Strüverite is a variety of rutile rich in tantalum and iron, with the formula (Ti,Ta,Fe)O₂, with variable proportions of niobium (Nb). When the proportion of Ta>Nb is called strüverite, but if Nb≥Ta the variety has been named ilmenorutile. The specimens from this locality in Madagascar have been mainly determined to be of the Ta-rich variety: strüverite. An interesting specimen with a very special chemistry.

Size: 2.1 x 1.1 x 1 cm.
Sold
RM3225   Almandine-Spessartine

Good size garnet crystal belonging to the almandine-spessartine series, usually with a predominance of the first one. The analyzes indicate the presence of Fe and Mn, with traces of Mg. These specimens were identified as pyrope (magnesium aluminosilicate), but the analytical results do not indicate this.

Size: 5.1 x 3.4 x 2.7 cm.
Main crystal: 2 cm.
50 €
RM3224   Almandine-Spessartine

Group of garnet crystals belonging to the almandine-spessartine series, usually with a predominance of the first one. The analyzes indicate the presence of Fe and Mn, with traces of Mg. These specimens were identified as pyrope (magnesium aluminosilicate), but the analytical results do not indicate this.

Size: 5 x 3.7 x 3 cm.
Main crystal: 2 cm.
Sold
RM3223   Almandine-Spessartine

Group of garnet crystals belonging to the almandine-spessartine series, usually with a predominance of the first one. The analyzes indicate the presence of Fe and Mn, with traces of Mg. These specimens were identified as pyrope (magnesium aluminosilicate), but the analytical results do not indicate this.

Size: 3.3 x 2.9 x 2.2 cm.
Main crystal: 2,1 cm.
45 €
RM3220   Almandine-Spessartine

Group of garnet crystals belonging to the almandine-spessartine series, usually with a predominance of the first one. The analyzes indicate the presence of Fe and Mn, with traces of Mg. These specimens were identified as pyrope (magnesium aluminosilicate), but the analytical results do not indicate this.

Size: 5.2 x 4.3 x 4.3 cm.
Main crystal: 2.7 cm.
Analyzed specimen with report
Sold
RM1834   Almandine-Spessartine

Very sharp almandine-spessartine crystal from Madagascar pegmatites. Rich in faces, a textbook specimen. Under the light you can see transparencies of reddish tones, in fact it is of intense red. It is disposed very aerial on the matrix with feldspar and quartz. Complete, perfect, of a considerable size... The garnets from Ialamitana, has been found to be an intermediate almandine-spessartine (Mineralogical Record, 29, p. 132). A great piece for garnet group lovers.

Sold