" I dont know what the scientific name of stiffness is but damping is not listed."
Stiffness is a _section_ property: it depends on the size and shape of the piece as well as the material. The relevant _material_ property is the 'Young's modulus', which is a measure of how much work it takes to stretch or compress a piece of a given size by a given amount in a given direction. Most wood has a much higher Young's modulus along the grain than across it, for example. Young's modulus is usually designated by the letter 'E'. Two parts of the same size made out of materials with the same E value will have the same stiffness.
Damping is not something that most structural engineers worry too much about, so you often don't get the measurement. It is measured in various ways, some of which are different enough to cause confusion even though they can be written down the same way. One measure, for example, is the 'Q value', which is a measure of the proportion of energy lost per cycle of vibration. Sometimes it's given in terms of 'cycles per second', and sometimes it's in terms of 'radians per second'. If it's the latter, there may or may not be a 'pi' lurking somewhere: they don't always put that in. One cycle per second equals 2*pi radians per second. Damping is also sometimes given as 'log decrement', which is 1/Q, by whichever method they're giving that, and tells you how many cycles (or 2pi radians) it takes for the signal to drop off by (sqrt 2)/2. Confused? I am.
For our purposes it's easy enough to hear any difference in damping that's likely to be significant. The measurement is simple enough in principle, and sometimes tricky in practice.