The Legislature shall have authority to define interest and fix maximum rates of interest; provided, however, in the absence of legislation fixing maximum rates of interest all contracts for a greater rate of interest than ten per centum (10%) per annum shall be deemed usurious; provided, further, that in contracts where no rate of interest is agreed upon, the rate shall not exceed six per centum (6%) per annum.
Official text of the Texas Constitution as published by the Texas Legislative Council.