>>1465082As someone who had to take mineralogy and some other bs that falls under geology:
>color (translucency, bending of light, hue, shininess, color left behind after scraping on a white ceramic tile)>shape (regularity, angles, mirror axis)>strength/hardnessBut generally you're better off just learning what kind of minerals are common in your region and checking them out at a museum or a research institute and learning the most common ones by heart.
In the field it's handy to carry a little bit of hydrochloric acid (to see if the rock contains calcium). First you add a few drops. If it doesn't foam straight away, you may need to scrape a bit off the rock and to get the oxidized layer away. (Dolomit only foams when the acid is applied to the scraped off dust)
Also look up the Mohs scale. You can make another distinction between rocks in the field by scraping the rock with your fingernail, a knife,...
You can also go all out and do different types of analysis including x-rays, SEM, microscopy,...
