Gem Tool - for Diamonds and Precious Gems

This tool will give you lots of information about many gem minerals. It will also give you a representation of the crystal habit of that mineral.

Just select the mineral that you are researching & click “Search”.

Please Select Gem Material      
Gem Material Zircon
Mohs Hardness 6.5 to 7.5
Refractive Index 1.777 to 1.987
Dispersion 0.039
Pleiochroism Varies
Specific Gravity 3.9 to 4.71
Double Refraction +0.059 to
Transparency Transparent
Fluorescence Varies
Chemical Composition Zr(SiO4)
Crystal System
Tetragonal System (four-sided or tetragonal),All three axes intersect at right angles. Two are equal in length and are in the same plane while the primary axis is either longer or shorter. Typical crystal shapes include four-sided pyramids and prisms and trapezohedrons. Occurences can also include eight-sided pyramids and double pyramids.


  • Color designations for pleichroism and fluorescence generally follow our color description system. A "+" can represent either "strong" or "dark".
  • "C" = colorless
  • Transparency designations are those most commonly accepted for gem / jewelry quality material