Rhizocarpon (order Lecanorales) A genus of crustose lichens in which the apothecia are lecideine and normally black. Spores are pale to dark brown, 1-or 3-septate to muriform. All species are found on rocks. R. geographicum occurs on siliceous rocks and walls, mainly in hilly districts; the thallus is bright yellow, surrounded and intersected by fine black lines, and dotted with small black apothecia.
More From encyclopedia.com
wolframite , wolframite Ore mineral for tungsten, with the formula (Fe,Mn)WO4; sp. gr. 7.0–7.5; hardness 5.0–5.5; monoclinic; grey-black to brownish-black; browni… chromite , chromite Member of the chromite group of minerals in the spinel group, Fe2+Cr2O4, along with magnesiochromite (MgCr2O4); sp. gr. 5.1; black; sub-meta… Biotite , biotite biotite An important rock-forming silicate mineral; a member of the mica group K2(Mg,Fe)6[Si3AlO10]2(OH,F)4, in which the Mg/Fe ratio is less… Titanite , sphene (titanite) A nesosilicate CaTiSiO4 (O,OH,F); sp. gr. 3.45–3.55; hardness 5; crystals wedge-shaped, occasionally massive; brown, grey, reddish… Igneous Rocks , Igneous rocks are formed by the cooling and hardening of molten magma. The word igneous comes from the Latin word igneus, meaning fire, and there are… Jack Black , Black, Jack Actor, singer, musician Jack Black is a one-man dynamo—a manic, scruffy ball of energy who has quietly been shaking up the entertainment…
About this article
Updated About encyclopedia.com content Print Article
You Might Also Like