Petrography lower if wholly or partly vitreous. The specific gravity of the more common rocks range from about 2.5 to 3.2. Archaeologists use petrography to identify mineral components in pottery. This information ties the artifacts to geological areas where the raw materials for the pottery were obtained. In addition to clay, potters often used rock fragments, usually called "temper" or "aplastics", to modify the clay's properties. The geological information obtained from the pottery components provides insight into how potters selected and used local and non-local resources. Archaeologists are able to determine whether pottery found in a particular location was locally produced
What Work Is workers, but artists, readers, and academics. Levine's poetry is accessible and moving and is utterly American. The poems in "What Work Is" are more subtle in their thematic construction. Levine does not use caricatures in these poems but instead intimates real blue-collar workers. Many of the poems give a representation of a station of life not common in the subject matter of contemporary American poetry. Although not all of "What Work Is" is primarily about the working class. Instead the poems have a wide range and variety. However many of these poems, despite their subject matter, show elements that identify