nugget
A small, solid piece of something valuable or important.
A nugget is a small, solid lump of something valuable or interesting. The word originally described chunks of precious metal, especially gold, found in streams or mines during gold rushes. Prospectors would pan for gold nuggets in rivers, hoping to find even a small piece that could make them rich.
Today, nugget describes anything compact and valuable. A chicken nugget is a small piece of breaded chicken. A nugget of wisdom is a short but meaningful piece of advice, like when your grandfather shares something he learned from years of experience. Information can come in nuggets too: a nugget of information might be a single useful fact hidden in a long article.
The word suggests something concentrated and worth keeping. When you're researching a topic and find one really helpful fact among pages of text, you've discovered a nugget. The value comes from being small but significant, like finding one perfect shell among thousands on a beach. That's why people talk about nuggets of truth, knowledge, or insight: small pieces that matter more than their size suggests.