It has slightly heart-shaped, rounded leaves with a bronze blush to them.
Garden retailers will sell this variously as Lemon, Orange, Lime, Eau de Cologne mint, etc. Botanists say they are really all the same, and that the suggestion of taste differences is more marketing than anything else. They agree that there is possibly a hint of citrus, but that how you interpret it is up to you. They also point that the probably the amount of citrus taste may vary based on how much sun, type of soil, etc, that the plant gets.
Bergamot Mint is used in the making of Chartreuse Liqueur.
Bergamot Mint has nothing to do with Bergamot tea or Early Grey tea. That is based on the aroma and flavour of Bergamot orange.
Not is it the same as Bergamot, the herb that is native to North America.
History Notes
Bergamot Mint is native to southern and central Europe, and has become naturalized in parts of North America.