- MIMOSA (Beta Crucis). Few are the first magnitude stars, as their apparent brightness requires either great luminosity, closeness, or both. Mimosa satisfies the first requirement.
- Siliceous rock (Wikipedia)
Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, or some types of sponges.