Hint: If you're not sure, you're most probably using transmitted light.
This specialised website aims at helping you correctly identify minerals based on the observation of properties seen under the microscope. The observable properties of a given mineral differ depending on the choice of optical path of the light generated by the telescope. This website contains datatables of properties of minerals under two possible paths: the transmitted light path and reflected light path.
In order to bring up a meaningful table of mineral properties, you first need to choose the setup relevant to your observations.
As things stand, the properties listed in the table on this website are properties meaningful only to those observing the minerals under transmitted or reflected light. We also plan to add, in the near future, a section on correctly identifying minerals when seen under the naked eye. In the mean time, there are many other websites available which provide this service. See the Sources and Resources page within the about page for a list of such websites we have found useful.
The Definitions page is purely theoretical, so can be explored without observing minerals. In addition, the About page has more details about the functions hosted on this website, including a page of Sources and Resources valuable to anybody wanting to learn more about geology.
Try following our very short walkthrough to learn the basic functionalities of the datatables. The tutorial will run supposing you have the Transmitted setup.