Farina (powder)
Protective powder on leaves (common in Echeveria) rubs off with touch; avoid wiping to keep a matte finish.
Hairs (tomentum)
Kalanchoe tomentosa carries soft hairs that reduce water loss and give a fuzzy feel.
Toothed/firm leaves
Aloe vera has firm, toothed margins; Crassula ovata has smooth, thick leaves on woody stems (tree-like form).
Use textures for ID + care
Powdery types dislike overhead watering; hairy leaves trap moisture and need airflow; toothed aloes prefer strong light with infrequent deep water.