| fluorite | <chemical> Calcium fluoride, a mineral of many different colours, white, yellow, purple, green, red, etc, often very beautiful, crystallizing commonly in cubes with perfect octahedral cleavage; also massive. It is used as a flux. Some varieties are used for ornamental vessels. Also called fluor spar, or simply fluor. Source: Websters Dictionary (01 Mar 1998) |
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| fluorite objective | Microscope objective corrected for spherical and chromatic aberration at two wavelengths. Better than an ordinary objective corrected at one wavelength but inferior to (and much cheaper than) a planapochromatic objective. (18 Nov 1997) |
| objective, fluorite | <microscopy> An objective using the mineral fluorite in its construction. It is usually intermediate between achromatic and apochromatic in correction, but may be more highly corrected. See: illumination, eyepiece. (05 Aug 1998) |
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