Gabbro is an intrusive igneous rock, dark in colour and often coarse grained. Chemically, it is equivalent to Basalt, and it forms when magma trapped underneath Earth’s crust cools down into a holocrystalline mass. It’s mainly composed of pyroxene, plagioclase feldspar (usually labradorite), and amphibole and olivine in a smaller percentage, and it has crystals with a size range of 1 millimeter or more. This composition gives Gabbro a dark colouration, usually black or dark green, but it can eventually have lighter crystals or speckles.
The difference between Gabbro and Basalt is that this last one is an extrusive rock which cools down rather quickly and have fine grained crystals, whilst Gabbro is an intrusive rocks, and cools down slowly, resulting in a coarse grained crystal composition. It also accepts a high polish, just like Granite does, in fact it is commonly commercialized as one.
This stone scores a solid 7 in the Mohs hardness scale, just as much as Quartzite, and in fact it’s a denser, tougher stone used both indoor and outdoor, for kitchen surfaces as well as landscaping.
Here is a list of the most common Gabbros, always commercialized as Granite:
(click on names to open material sheet)
- Absolute Black
- Angola Black
- Bengal Black
- Black Pearl
- Emerald Pearl
- Nero Impala
- Stargate
- Star Galaxy
- Ubatuba
- Volga Blue
- Zimbabwe Black
The Stone Wiz 