Magnetite on Matrix
$45.00
Magnetite is an important iron ore, along with hematite.
It is usually easily distinguished by being strongly magnetic, with black octahedral crystals.
Nanoinclusions of magnetite crystals cause the iridescence of Rainbow obsidian (Nadin, 2007). Extremely thin layers of 200-nm octahedral crystals of magnetite give some basalt surfaces an iridescent sheen (Nadin, 2007).
May precipitate from supersaturated volcanic gas due to its cooling as shown in an experiment by Africano et al. (2002) (actually a predominant precipitate from ca. 850 down to 650oC in this particular experiment).
1 in stock
Description
Magnetite Crystals on grey matrix from Broken Hill, NSW Australia
Formula | Fe2+Fe3+2O4 |
As A Commodity | |
Colour | Greyish black or iron black |
Lustre | Metallic, Sub-Metallic |
Hardness | 5½ - 6½ |
Specific Gravity | 5.175 |
Crystal System | Isometric |
Member of | |
Name | Originally called lodestone as early as 1548 and by other names. Named in 1845 by Wilhelm Karl von Haidinger for the locality at Magnesia, Greece (site for lodestone). |
(Courtesy Mindat)
Magnetite is a key iron ore, easily identified by its strong magnetism and black octahedral crystals.
Nanoinclusions of magnetite crystals cause the iridescence in rainbow obsidian (Nadin, 2007) and give some basalt surfaces an iridescent sheen with 200-nm thin layers (Nadin, 2007).
It can precipitate from cooling supersaturated volcanic gas, as shown in Africano et al.’s experiment (2002), predominantly forming between 850 to 650°C.
Additional information
| Weight | 100 kg |
|---|---|
| Dimensions | 12.5 × 7 × 1 cm |
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