  The production and freeze-out conditions of strange particles, produced in
Au+Au collisions at RHIC energies, are studied within microscopic transport
model. The system of final particles can be represented as a core, containing
the particles which are still interacting with each other, and a halo, in which
the particles have already decoupled from the system. In microscopic
calculations hadrons are continuously emitted from the whole reaction volume.
At RHIC, however, significant fractions of both mesons and baryons are emitted
from the surface region within the first two fm/c. Different species decouple
at different times. Strange mesons (kaons and $\phi$) are frozen at earlier
times and, therefore, can probe earlier stages of the reaction.
