Science and techniques

including crystallography, chemistry, physical properties and analytical techniques used in mineralogy

WebElements, Periodic Table of the Elements
where each chemical element contains a link to a page that explains its chemical properties, health effects, environmental effects, application data. 

Crystal chemistry of some Common Mineral Groups
briefly discusses the crystal chemistry of the mineral groups like garnet, plagioclase, pyroxene, mica (muscovite and biotite), amphibole (mainly about hornblende). By Dave Waters, Department of Earth Sciences, University of Oxford.
The International Union of Crystallography
the IUCr is an International Scientific Union. Its objectives are to promote international cooperation in crystallography and to contribute to all aspects of crystallography, to promote international publication of crystallographic research, to facilitate standardization of methods, units, nomenclatures and symbols, and to form a focus for the relations of crystallography to other sciences. 

Crystal Plane d-spacings and Interplanar Angles
Calculates d-spacings and interplanar angles from cell parameters , program by Brad De Gregorio
 Physical Properties
Mineral Spectroscopy Server 
provides information about color in minerals and access to data on Mineral Absorption Spectra in the visible and infrared regions of the spectrum and Raman spectra of minerals

Optical mineralogy
lecture notes, department of earth sciences at Brock University, Ontario, Canada

Optical Mineralogy tools
tools that supplement conventional optical mineralogy course materials by Olaf Medenbach at the Institut für Geologie, Mineralogie und Geophysik

 Analytical Techniques
The Electron Probe Technique
information on the microprobe and SEM techniques and a glossary of terms. (University of Oregon, microprobe lab)