  While quasi-two-dimensional (layered) materials can be highly anisotropic,
their asymptotic long-distance behavior generally reflects the properties of a
fully three dimensional phase of matter. However, certain topologically ordered
quantum phases with an emergent 2+1 dimensional gauge symmetry can be
asymptotically impervious to interplane couplings. We discuss the stability of
such "floating topological phases", as well as their diagnosis by means of a
non-local order parameter. Such a phase can produce a divergent ratio
$\rho_{\perp}/\rho_{\parallel}$ of the inter-layer to intra-layer resistivity
as $T\to 0$, even in an insulator where both $\rho_{\perp}$ and
$\rho_\parallel$ individually diverge. Experimental observation of such a
divergence would constitute proof of the existence of a topological (e.g. spin
liquid) phase.
