TERRIUM — A mineralogy cabinet


Corindón Rubí Malgache

Corindón is a mineral with formula Al₂O₃, in the Óxidos group. This specimen comes from Zazafotsy, Amboarohy, Ihosy District, Ihorombe, Madagascar and joined the Terrium collection in 1998.

Corindón Rubí Malgache from Zazafotsy, Amboarohy, Ihosy District, Ihorombe, Madagascar — Terrium

Description

Dull, doubly terminated hexagonal prism with striations and a small inclusion. Typical of Malagasy rubies with high iron content. Strong UV response.

History of this specimen

Comes with the original label from the Milan shop "Bottega delle Pietre", active during the 1970–2000 period. The original handwritten label reads "Rubino – Madagascar".

About Corindón

Red variety of corundum, coloured by chromium and modulated by iron. Its hardness (9 on the Mohs scale) and lustre make it one of the most valued gemstones. In Malagasy specimens, the violaceous or pinkish tone is due to the Fe³⁺/Cr³⁺ ratio, giving them a cooler appearance than Burmese rubies.

About the locality

The Zazafotsy deposit comprises corundum formed in high-grade metamorphic rocks, mainly Precambrian gneisses and marbles. Rubies from this area are characterised by a high iron content, which shifts the red colouration towards violaceous or purple tones and reduces the typical vitreous lustre.

Technical data

Catalogue No.
0262
Composition
Al₂O₃
Name
Corindón
Variety
Rubí Malgache
Group
Óxidos
Category
Estélites
Mine
Zazafotsy
District / Municipality
Amboarohy
Province
Ihosy District
Region
Ihorombe
Country
Madagascar
Size (cm)
2.5 x 0.8 x 0.7
Weight
8 g
Acquired
1998
Ex-collection
Sergio Petretich
Etymology
From Latin "rubeus", red. The term "ruby" is reserved for red corundum, while the blue varieties are called sapphires.
Quality
Muy buena
Value trend
Estable

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