Citrine is considered the "merchant stone" due to it's ability to promote abundance, creativity and power. It also stimulates the crown chakra and is therefore helpful in stimulating the mind. It also helps align the chakras and balances energy.
The heart has long been used as a symbol to refer to the spiritual, emotional, moral, and in the past, the intellectual core of a human being. As the heart was once widely believed to be the seat of the human soul, the word heart continues to be used poetically to refer to the soul, and stylized depictions of hearts are used as prevalent symbols representing love.