Suppose classical "pure matter" as you describe it existed and suppose a spherical volume $V$ of $1\,\text{m}^3$ of this stuff has mass $M$. Since it exists of pure matter only, one expects a uniform mass density $\rho$.

Now you can zoom in on that volume forever and never would you reach a point where you see 'bubbles' or any space between things. Just the same old impenetrable stuff, forever. So $M$ can't go to zero as you take $V$ down to zero, which would mean an infinite mass density. Therefore $1\,\text{m}^3$ of it would have infinite mass.

Suppose classical "pure matter" as you describe it existed and suppose a spherical volume $V$ of $1\,\text{m}^3$ of this stuff has mass $M$. Since it exists of pure matter only, one expects a uniform mass density $\rho$ and $M$ is just $\rho V$. So you'd have to define the mass density of "pure matter" to answer your question.

Say you make it 1 Planck mass per Planck length cubed, a natural density to assume for your hypothetical pure matter:

$$\rho_P = \frac{m_P}{{l_P}^3} = 5.15500\times10^{96}\,\text{kg}\,\text{m}^{-3}.$$

Now, that's heavy stuff.