Have a fluted, oyster-shell shape & soft texture.
Are well known for their smooth texture and subtle, oyster-like flavour.
Available in white, beige, pink or yellow varieties - the white is most commonly available.

In commercially available mushrooms look for those with a firm texture and even colour with tightly-closed caps.
If the gills are showing, it's an indication of age, and they are probably past their prime.
Broken, damaged and discoloured mushrooms with soft spots should be avoided.