The establishment of EVISA is funded by the EU through
the Fifth Framework Programme (G7RT- CT- 2002- 05112).
Supporters of EVISA includes:
A technique for the semiquantitative mineralogical analysis of a sample
of rock by measuring the diffraction peaks in X-rays diffracted by the
sample. The position of the diffraction peaks is a measure of the
distance between discrete crystallographic diffracting planes within
minerals, while their intensity indicates the quantity of the mineral.
The technique is only semiquantitative because the size and shape of
the diffraction peak are strongly influenced by the geometry of the
measurement, for example orientation of the minerals, and sample
preparation. Fine particles such as clays must be separated from larger
particles and measured separately if they are to be detected properly.
To reduce errors associated with preferred orientation of minerals,
samples are most commonly ground to a powder before analysis, a
technique known as powder X-ray diffraction.
The term "X-ray diffraction" was found in the following pages: