首楞嚴義疏注經 8.116

8.116

琉璃空也，精金中也，現即假也。淨寶、精金互相映現，無礙融通，不一不異。以此妙心而為所依，然後出生無量德用，故名治地。

Vaidūrya is emptiness, refined gold is the Middle, and the appearance is provisionality. The pure jewel and refined gold reflect each other, unhindered and interfused, neither one nor different. Relying on this wondrous mind as support, it subsequently produces immeasurable virtues and functions; hence it is called cultivating the ground.