Thickness and tactile properties

густая борода a thick beard
редкая борода a sparse beard
жидкая борода; тощая борода a scraggly beard, a sparse beard
NB The adjectives жидкая and тощая, which indicate a negative attitude on the part of the speaker, are more often used with the diminutive бородка. The adjective редкая is used with борода as a neutral modifier, with no pejorative overtones.
жёсткая борода a stiff, wiry beard
колючая борода a prickly beard
мягкая борода a soft beard
шелковистая борода a silky beard
пушистая борода a fluffy beard
пышная борода a lush beard