A micromixing chamber, roughly in the form of an hourglass, having a first outer end with a tangential inflow opening and a second outer end with a tangential outflow opening. The mixing chamber in the overall flow direction first narrows more or less gradually and subsequently widens more or less abruptly. The micromixer may be made at least partially of glass, or at least partially of a plurality of glass plates. A micromixer having a plurality of such micromixing chambers connected fluidically in series is also disclosed. Methods for manufacturing such a micromixing chamber of such a micromixer, as well as method for mixing by means of such a micromixing chamber or by means of such a micromixer, are disclosed.