Mineral physics is a field of materials physics and materials chemistry confined to the study of materials pertinent to the Earth and planetary interiors. In the last two decades, emphasis has been given to research on the values of physical properties in materials appropriate to the Earth's mantle and core.
Braginsky and Roberts [1995] listed the physical properties that play a key role in their analysis of convection of the Earth's core and the dynamo. These connect mineral physics to geomagnetism of the core. This review will be concerned primarily with progress made in the last four years in refining values of these properties.
Because the core is composed primarily of iron diluted with light elements [ Birch, 1952, 1964], the physics of iron must be well understood before successful perturbations to assess the effect of impurities on the desired parameters of the real core material can be made.
The physical properties listed by Braginsky
and Roberts [1995] are calculated using
and 
, taken from Stacey [1995],
and following a paper by Anderson [1994] in which
the best estimate of the melting temperature
of pure iron at 330 GPa, 
,
is given as 6000 K. These core physical properties are:
Mineral physicists have expended much effort
to find the melting temperature of pure iron
at the inner core-outer core pressure, which must
be known before 
can be found.
Searching for 
has comprised
the bulk of recent research in this field.
The crystallographic structure of the iron phase
at inner core conditions must be known to establish the
density drop due to impurities, and this
drives mineral physicists to seek the correct phase diagram of iron
at high 
and T. The quantity of impurities
in the inner core then establishes 
from 
.
At the end of the last quadrennium
(1987--1990), there was a hardening of
conflicting opinions on the position of the high 
melting curve of iron, with Williams et al. [1991]
supporting a high melting curve, and
Boehler et al. [1990] supporting a relatively
low melting curve. The matter was the subject of controversial
debates reflected in the papers of Williams et al. [1991]
and Boehler et al. [1990] and continued by
Anderson [1992] and Jeanloz [1992].
Problems involved in all experiments
were emphasized by Duba [1992].
In the current quadrennium (1991--1994),
many more contributions to experiments and theories
of iron (especially concerning 
of iron) have appeared. There has been a substantial
increase in data since the review by Jeanloz [1990].
This outpouring of new work is evidenced, for example,
by two meetings sponsored by the Institute of Geophysics
and Planetary Physics, University of California.
These were named the ``Ironworkers Convention''
by JGR's associate editor for the proceedings, T.J. Shankland.
The First Ironworkers ``convention'' was held in
Los Alamos in 1989, and the proceedings were published
in the December 1990 issue of The Journal
of Geophysical Research. The second ``convention'' was held in
Colorado Springs in July 1993, in collaboration with the
AIRAPT (International Association for Research and Advancement
of Science and Technology), and its proceedings were published
with other AIRAPT papers (see Schmidt et al., eds.,
High Pressure Science and Technology--1993,
various references). As a result of all the recent activity
on iron, the Jeanloz-Boehler controversy has declined
in visibility, and other controversies now dominate research on
iron at high P. In fact, the Jeanloz-Boehler controversy appears to
be resolved, as discussed in the next section.