Daily Archives: May 18, 2015

Rough Ethiopian Opal (Kolekcja - Lech Darski) — Before they are cut and polished into gems, birthstones are natural crystals. Take a look at examples of each of the beautiful birthstone minerals: January Birthstone – Garnet [Chemical Formula X3Y2(SiO4)3] Color: any, but birthstone is usually red Hardness: 6.5 to 7.5 Crystal Habit: Cubic or Rhombic Dodecahedron The traditional […]

Birthstone Minerals – Chemical Formula and Appearance

This entry was posted on May 18, 2015 by Anne Helmenstine (updated on January 29, 2023)

Helium Atom — Basic Helium Facts Name: Helium Atomic Number: 2 Element Symbol: He Group: 18 Period: 1 Block: s Element Family: Noble Gas Atomic Mass: 4.002602(2) Electron Configuration: 1s2 Discovery: First identified: Pierre Janssen in 1868. First Isolated: Sir William Ramsay in 1895. Janssen was a French astronomer who observed a new yellow spectral line while observing a […]

Helium Facts – Atomic Number 2 or He

This entry was posted on May 18, 2015 by Todd Helmenstine (updated on February 21, 2023)