Collection: Gabbro or Merlinite

Gabbro is a plutonic igneous rock , meaning that it formed from the slow cooling of magma deep in the Earth's crust. It is one of the deep-sea equivalents of basalt , which forms on the surface by rapid cooling.

Characteristics of gabbro:

• Color : Generally dark, ranging from dark gray to black.

• Texture : grainy (crystals visible to the naked eye), due to its slow cooling.

• Main minerals :

  • Plagioclases (mainly labradorite)

  • Pyroxenes (often augite)

  • Sometimes olivine (in olivine gabbros)

• Density : relatively high (approximately 2.9 to 3.1 g/cm³)

Training:

Gabbro forms when basaltic magma cools slowly in deep magma chambers , such as those found beneath mid-ocean ridges or in rift zones.

Where is it found?

• Mid-ocean ridges : It constitutes a large part of the oceanic crust (in the series called ophiolite).

• Continental intrusive massifs : For example, in the Alps, the Appalachians or certain massifs in Scandinavia.

Uses:

• Building stone : in paving stones or slabs.

• Ornamental stone : sometimes used in interior decoration.

• Mineral source : Some olivine-rich gabbros may contain metals such as nickel , chromium , or platinum .

Difference with basalt:

• Same basic chemical composition, but different texture : basalt is fine-grained (rapid cooling), while gabbro is coarse-grained (slow cooling).