Definition of "regulus" []

• The metallic mass that sinks to the bottom of a furnace or crucible during smelting. (noun)
• A relatively impure intermediate product of various ores in smelting. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Chinese antimony is exported in part as antimony crude (lumps of needle-like antimony sulphide), and in part as antimony regulus, which is about 99 per cent pure metal."
• "A regulus is a sulphide of copper and iron, carrying from"
• "The imports of raw ores and partly reduced ores called "regulus," come mainly from Mexico to New York and"