In that Buddha-land, the earth is composed of seven jewels — namely, gold, silver, beryl, coral, amber, agate and ruby — which have spontaneously appeared. The land itself is so vast, spreading boundlessly to the farthest extent, that it is impossible to know its limit. All the rays of light from those jewels intermingle and create manifold reflections, producing a dazzling illumination. Those pure, superb and exquisite adornments are unsurpassed in all the worlds of the ten quarters.
(The Sutra of Immeasurable Life)