Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral.
In kasta oo qaar badan oo ka mid ah magacyada soo jireenka ahi taariikh ahaan ka soo if baxeen midabka macdanta, haddana magacyada hadda sayniska ee saynisku waxaay tixraac u yihiin kaabayaasha macdanta.