Detail Whole Slab
to overview

Tropical Black

The close-up view of each stone type shows a relatively true image of the crystalline structure and the colouring. This is suitable for grained slabs to a limited extend only. In regard to the colour matching, please take an original sample of the stone from your furniture store as a basis.


The dark portions, making for approximately two third of the rock, are rich of black, laminate biotitemica together with light reddish alkali feldspar and grey, transparent quartz. In this case, the grains arevery fine and the minerals are clearly aligned in parallel. By contrast, the lighter, coarser crystallineclouds are almost free from biotite and they consist almost exclusively of red alkali feldspar, light,virtually colourless plagioclase and transparent quartz. Several centimetres long fine hairline cracks can actually be found, especially in these zones, caused by the different cooling temperatures of thedifferent minerals. They are visible, sometimes even perceptible and criss-cross the material also overlarger thicknesses, but have no influence on the static characteristics of the material, as they are growntogether crystalline – it is similar resistant like granite.


Migmatite is highly metamorphous rock. It was generated under very high pressures and temperatures in the root zones of folded up mountain ranges. Typical is a dark, slate-like old remnant (melanosome), into which brighter, already molten portions (leucosome) are imbedded. After erosion of the mountains, these often very changeable rocks were laid bare due to erosion of the covering mountain over the millions of years. Very large, very variable deposits are quarried in large quantities in the continental cores of Northern and Southern America, India and Africa. As a rule, migmatite is very changeable. Every plate is unique.

Hardness Hard Stone
Structure Type Slab with Irregular Pattern
Synonyms Preto Tropical
Group Metamorphite
Petrographic Assignment Gneiss (Migmatite)
Age 570 million years (Precambrian)
Colouring Minerals Grey feldspar and quartz, red alkali feldspar, black biotite mica
Average Hardness 6-7 (according to Mohs’s hardness scale 1-10)
Deposit USA