The mass of an object does not change depending on location.
quality and quantity
Refers to both the quality and the quantity of something, often used in set phrases like 質量ともに (in both quality and quantity).
See also: 質量ともに
この製品は質量ともに優れている。
This product is excellent in both quality and quantity.
We measure the mass of this object.
The Earth has a greater mass than the Moon.
molar mass
invariant mass