Large polished slab, possibly meant as a paper weight. 6 3/4" x 4 3/4" x 5/8" thick with rounded corners and polished faces. 1118 grams-by far the largest piece we have been able to locate. The largest on the market at this writing is 253 g. offered at $100.00. This example is doubly useful as having been polished, regular shaped pieces may be cut with minimum waste. Or, simply display it as a natural history specimen and massive gem stone. Small chip to one corner.