It is commonly called alumina, and may also be called aloxide, aloxite, or alundum depending on particular forms or applications. It commonly occurs in its crystalline polymorphic phase Î±-Al 2 O 3, in which it composes the mineral corundum, varieties of which form the precious gemstones ruby and sapphire.
rain cloud. (meteorology). Any cloud from which rain falls; a popular term having no technical denotation. 1  Facebook. 2  Twitter.
Fog- Fog is a cloud that has the base on the earth's surface. Fractus- Fractus are also known as scud and cloud tags. They are isolated low level stratus clouds that can often be seen around the base of thunderstorms. They often look unorganized and flow with the low level wind.