Curated category
Materials
- GemstoneA gemstone is a piece of mineral crystal used to make jewelry or other adornments. Webster Online Dictionary defines the term broadly enough to include…
- GlassA single crystal has atoms in a near-perfect periodic arrangement. An amorphous solid such as glass has no periodic arrangement even microscopically.
- WoodIn the Canadian province of New Brunswick, scientists uncovered plant fossils dating back approximately 395 to 400 million years.
- Rock (geology)The Grand Canyon cuts through layers of sedimentary rocks, revealing a vertical history written in stone. Geologists define rock as any naturally occurring…