igneous
Indigo Gabbro (also known as Mystic Merlinite)
Gabbro (composed of Plagioclase Feldspar, Pyroxene, and minor Magnetite/Ilmenite)
Hardness: 6-7 on Mohs scale; Color: Mottled black, dark grey, and light green/white; Luster: Vitreous to sub-metallic (when polished); Crystal Structure: Phaneritic (coarse-grained) crystalline; Specific Gravity: 2.7-3.3
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled black, dark grey, and light green/white
- Luster
- Vitreous to sub-metallic (when polished)
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled black, dark grey, and light green/white; Luster: Vitreous to sub-metallic (when polished); Crystal Structure: Phaneritic (coarse-grained) crystalline; Specific Gravity: 2.7-3.3
Formation & geological history
Formed from the slow cooling of magnesium-rich and iron-rich magma deep beneath the Earth's crust (plutonic formation). These specimens are often millions of years old, typically found in late Precambrian or Paleozoic formations.
Uses & applications
Primarily used for ornamental purposes, tumbled stones, jewelry (cabochons), and as a popular stone among crystal collectors and metaphysical practitioners.
Geological facts
Despite the trade name 'Mystic Merlinite', it is not a true Agate or Merlinite (Dendritic Opal). It is a plutonic igneous rock. It is prized by collectors for its chatoyant-like shifts in color when moved under light.
Field identification & locations
Identify in the field by its coarse-grained 'salt and pepper' appearance and lack of quartz. Commonly found in Madagascar, Turkey, and portions of the United Kingdom. To identify, check for a heavy weight relative to size and the presence of dark, blocky pyroxene crystals.
