South carolina constitution
Article V: judicial department
Section 22

The petit jury of the Circuit Court shall consist of twelve members and the number of jurors of other courts must be determined by law. All jurors in any trial court must agree to a verdict in order to render the same. The grand jury of each county, and the state grand jury, as the General Assembly may establish by general law, shall consist of eighteen members, twelve of whom must agree in a matter before it can be submitted to the Court. Each juror must be a resident of this State and have such other qualifications as the General Assembly may prescribe.