Ruby is a red variety of corundum, colored by trace chromium impurities. In materials science, its value comes from controlled composition and crystal quality: tiny changes in impurity levels affect color, transparency, and durability. That makes ruby a good example of how a precise manufacturing process can create a predictable, high-value material.
In cyber security, the word Ruby often refers to the Ruby programming language, not the gemstone. Ruby appears in automation scripts, web tooling, and offensive frameworks such as Metasploit, where modules and proof-of-concept exploits are frequently written in Ruby. Defenders also use Ruby for log parsing, testing, and workflow automation. The security lesson is the same as with the stone: reliable results depend on knowing exactly what was built, how it was built, and whether it can be trusted.