The seal of the board shall be an embossed circular seal consisting of two concentric circles. The diameter of the inner circle shall be approximately 60% of the size of the outer circle which shall be the official seal of the State of Texas. The area between the two circles shall contain the wording "Texas Board of Professional Engineers and Land Surveyors." The executive director shall be the custodian of the seal. The seal may be reproduced in other sizes provided the dimensions remain proportionate.