Physical Properties of Rubidium and Francium
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Grayish White
  
NA
  
Luster
NA
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Speed of Sound
1,300.00 m/s
  
99+
Not Available
  
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available