This is the talk page for discussing improvements to the Viking Age article. This is not a forum for general discussion of the article's subject. Put new text under old text. Click here to start a new topic. Please sign and date your posts by typing four tildes (~~~~).
In addition, it must be hard and durable. Its value increases if it is also rare.The beauty of a gem is measured in terms of its clarity, brilliance, and color. Comments
who knows what. To be classified as a mineral, a substance must be an inorganic, naturally formed solid, with a specific chemical formula and a fixed internal structure. For example, coal is not a mineral (it's organic), but snow meets all five (5) requirements and therefore is a mineral. Luster: The quantity and quality of light reflected from the surface. Most identification schemes begin with a simple classification based on luster.