Heavy metals only mercury, lead and bismuth meet all of them. Despite this lack of agreement, the term (plural or singular) is widely used in science. A density of more than 5 g/cm is sometimes quoted as a commonly used criterion and is used in the body of this article. The earliest known metals—common metals such as iron, copper, and tin, and precious metals such as silver, gold, and platinum—are heavy metals. From 1809 onwards, light metals, such as magnesium, aluminium, and titanium, were discovered, as well as less well-known heavy metals including gallium, thallium, and hafnium. Some heavy metals are either
The Unbeheaded King Xylar and Othomae. As usual, the political constraints under which the protagonist labor are at least as important as the fantastic element. The decidedly unromantic, even hardscrabble circumstances under which he must achieve his goals leaven the fantasy with a strong sense of reality, and highlight de Camp's unusual reversal of the genre's stereotypical rags to riches theme. The Unbeheaded King The Unbeheaded King is a fantasy novel by American writer L. Sprague de Camp, the fourth book of his Novarian series and the third in the "Reluctant King" trilogy featuring King Jorian of Xylar. It was first published as