Quartz Sand Grain

Transmitted Circular Polarized Light Illumination

The transformer was an "air-breather". The filtration was not very effective and as a result
significant quantities of airborne particles entered into the system. This particle is identified
as quartz by its low birefringence and moderate refractive indices,near that of the Transformer
oil. It is uniaxial and has a positive optical sign. The grain is rounded and has some attached
clay. This combination of features rules out its use as a filler in any of the transformer components
and rules out it being an abrasive residue. This is a sand grain that has entered the system