Labrador Black and Gold
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. While feldspar is usually light, here it has a fairly dark shade due to brownish clouding of the crystals, in which the rather few really black augite crystals become rather invisible. The often visible glittering effect in rock of this kind is generated by light refraction at the gap surfaces and the twin faces of the labradorite. Despite high scratch hardness it is not as acid-resistant as granite!
Generation of this rare and extremely attractive plutonite rock is worldwide limited to a certain period of Pre-Cambrian. Anorthosite belongs also to the oldest rocks of the earth proof of larger areas of it on the moon has also been given! Anorthosite occurs in the crystalline base of the continents, partly in giant complexes, partly as successors of gabbro and it is increasingly processed.
|Structure Type||Homogeneous Structure|
|Group||Plutonic rock - plutonite|
|Petrographic Assignment||Granite - anorthosite|
|Age||Over 1 billion years (Pre-Cambrian)|
|Colouring Minerals||Dark, glittering feldspar (labradorite)|
|Average Hardness||6 (according to Mohs's hardness scale 1-10) / Natural stone|
|Deposit||South of Sa da Bandeira, Angola|