Filter, 35mm slide sized glass protected polarising filter. This simple filter has a piece of good quality polarising sheet, sandwiched between glass. Ideally 2 filters should be purchased – A single filter is used to help understand the nature of polarised light; a single filter can also be used to show ‘Dichroism or Pleochroism’ in coloured doubly refractive stones. When used with the second filter the effects of partial or total extinction can be seen; or, when a gemstone is held between them in the ‘crossed’ position the effects of strain, single or double refraction and dichroism or pleochroism can be seen.

These 2 filters in effect can be used as a simple polariscope. A single filter can also be used ‘in the field’ in combination with a small torch to see dichroism or pleochroism in doubly refractive gemstones, whether cut or in the uncut state.

£50.00 (excludes VAT where applicable)