Sentence:  First of all , the six figures of the Buddha you heisted - four Siamese heads , a black <WSD>obsidian</WSD> statuette in the earth touching position , and a large brass figure of the Dying Buddha on a teakwood base . 
Meaning of the word marked with <WSD> tags:  acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces