4 Beryllium Be

Beryllium is a rare element, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays.
Has high flexural rigidity, thermal stability, thermal conductivity and low density.
It is relatively transparent to the x-ray and other ionizing radiation because of its low density and atomic mass.
Beryllium is created in stars, both stable and unstable isotopes but the radioisotopes do not last long.

Health: beryllium is relatively safe to use; exposure can lead to immune response and can over time develop chronic beryllium disease.
Approximately 25 micrograms of beryllium is found in human body.
Is similar to magnesium and can displace it from enzymes causing them to malfunction.

Uses:
Aerospace, missiles, spacecraft and satellites.
Used in particle detector as window because is transparent to x-ray and other ionizing radiation.
Mixed with copper forms beryllium copper that is 6 times stronger than copper alone, with high elasticity, strength and hardness, good corrosion and fatigue resistance. applications include non-sparking tools that are used near flamable gases: wrench and other tools.
Beryllium mirrors are used in meteorogical satellites because of low weight and long-term stability.
Because of non-magnetic characteristic, it is used in magnetic resonance imaginc MRI, military use, radar, communication, magnetrons in microwave.
Beryllium is a component in dental alloys.
Gyroscope.

Where to find it:
x-ray window, gyroscope, missle parts

Characteristics:
Atomic number 4; atomic weight 9,0121831
Color slate gray metalic
Crystal structure: hexagonal close-packed
Speed of sound in solid: 12,890 m/s
Density 1,848 g/cm cube
Hardness: 5,5
Melting point 1287 C
Boiling point 2470 C
Phase at 20 C: solid
Electrical type: conductor
Magnetic type: diamagnetic
Abundance 0,00019% in earth crust
Isotopes from Be 5 to Be 16
Be 9 is stable with 100% abundance
Be 7 with half-life of 63,12 days; abundance: traces: decay mode ε electron capture and gamma; product Li 7
Be 10 with half-life of 1,39x10 to the power of 6 years; abundance traces; decay mode B negative; product B 10 (boron)

Minerals: Beryl, Aquamarine, Emerald, Chrysoberyl, Londonite-Rhodizite, Phenakite, Hydroxilherderite

Beryl:

Smarald - Emerald - variety of Beryl