Copper and Gold have good properties. when we make a pyramid yantra from completely from them all 91 space chambers are short circuited. To avoid the short circuit problem, copper or gold has too be used partially or in appropriate place or proportion. the best example are millions of the temples where only a small copper or gold yantra is fixed at the bottom and tip of the temple. The whole temple is not made of copper. So if you need to use copper or gold in pyramid yantra, use it in a small proportion at the base. short circuit in case of copper in a copper pyramid leads to all 91 space chambers being short circuited.