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.
Anorthosite consists almost exclusively of Ca-rich Plagioclase Feldspar. This rock is extraordinarily coarse-crystalline, whereby the large crystals are interspersed with fine hairline cracks (cooling cracks). The dark brown, up to 10 cm large crystals are nested without directional alignment and occasionally show double lamella. Feldspar has a scratch resistance similar to steel.
Calcium-rich, Silicate-containing melt penetrated the earth crust from the depth. It solidified some kilometres below the earth surface after extremely slow cooling, whereby giant crystals were formed. In this case, ideal crystal forms cannot be expected, as the crystals could not freely form due to the spatial constraints. Until this plutonic rock reached the surface, it was exposed to enormous pressure due to superposition, which, together with displacement forces in the earth crust, caused tearing and bursting of the rock material. Therefore, clearly visible and perceptive fine hairline cracks can be found in the polished surfaces, which seemingly go right through the thickness of the material. However, these have grown together as a mineral over the millions of years during their generation and have no influence on the technical properties of this material.
|Structure Type||Homogeneous Structure|
|Synonyms||Brown Antique, Marrom Antik, Angola Brown|
|Group||Plutonic rock (Plutonite)|
|Age||Approximately 1.5 Billion years (Pre-Cambrian)|
|Colouring Minerals||Dark-brown Feldspar|
|Average Hardness||6-7 (according to Mohs's hardness scale 1-10) / Natural stone|
|Deposit||Angola, near Sa da Bandeira|