Know all about Gneiss and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss belongs to Metamorphic Rocks while Picrite belongs to Igneous Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Picrite is Earthy, Rough. Gneiss appears Foliated and Picrite appears Rough and Shiny. The luster of Gneiss is dull while that of Picrite is subvitreous to dull. Gneiss is available in black, brown, pink, red, white colors whereas Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).