Mother Lode

The "Mother Lode" refers to a rich underground vein of valuable minerals, typically gold or silver, that runs deep within a mountain or earth. It is often the main source of precious metals for mining operations, representing a significant and productive deposit. Historically, the term became popular during the California Gold Rush, symbolizing a major find that could fulfill many expectations of wealth. In general, “Mother Lode” can also metaphorically describe any abundant and reliable source of valuable resources or information.