Amorphous is the answer. A glass is an amorphous solid.
I am assuming you are talking about Neon. The rate of diffusion is directly proportional to the molar mass of the gas. Since neon has a molar mass of 20.18 grams, the gas must have a lower molar mass and must be a gas at 273 Kelvin. There are several elements that fulfill this criteria: Hydrogen, Helium, Oxygen, Nitrogen, and Fluorine.
(60)/(60+5.05)=.922367 C
1-0.922367=0.07763259 H
(0.922367)(78.12)=72.05534204 C
(0.07763259)(78.12)=6.06 H
72.05534204/(12.01)=6 C
6.06/1.01=6 H
Empirical= CH
Molecular=C6H6