Experiment to investigate the anisotropy of a small crystal

[Open Intelligence]

Measure V and I in three different (mutually perpendicular) directions so that the resistance can be found and hence the resistivity can be calculated from the measurement of the length and cross-sectional area of the crystal.

resistivity = AV/IL

Making connections to the crystal can be difficult because of its small size.
Use pins with wires soldered to them.

If the resistivity is large, consider using a very sensitive microammeter instead of an ammeter or use a higher voltage.

Since the crystal might be in a very irregular shape, it might be difficult to measure the length. However, using vernier callipers or micrometer screwgauge will give a reasonable estimate of the dimensions of the crystal.