Period 6 element years and is used in medical applications, industrial gauges, and hydrology. Although the element is only mildly toxic, it is a hazardous material as a metal and its radioisotopes present a high health risk in case of radioactivity releases. Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with water and carbon dioxide and is
Sterling silver items in the “New World” ranging from simple buckles to ornate Rococo coffee pots. Although silversmiths of this era were typically familiar with all precious metals, they primarily worked in sterling silver. The colonies lacked an assay office during this time (the first would be established in 1814), so American silversmiths adhered to the standard set by the London Goldsmiths Company: sterling silver consisted of 91.5 - 92.5% by weight silver and 8.5–7.5 wt% copper. Stamping each of their pieces with their personal maker's mark, colonial silversmiths relied upon their own status to guarantee the quality and composition of their