Calcite

Sylvania Minerals Quarry has produced top-tier specimens of calcite and celestine for many decades, two of the classic mineral species associated with Michigan's Lower Peninsula. The state of Michigan serves as a textbook example of a sedimentary basin: a low area of Earth's crust in which sediment accumulates and eventually becomes rock. When the bedrock layers of a sedimentary basin are mapped, the aerial view appears as a "bullseye" shape, with the youngest deposits in the center and the oldest at the outermost ring. Because of this, quarries in southeast Michigan are able to access the Bois Blanc Formation, a Devonian-aged geological unit made up of limestone and dolostone. Certain layers of the Bois Blanc Formation contain crystal-filled pockets, or "vugs," where these fabulous celestine and calcite crystals are found. Since these layers are only exposed in aggregate quarries, very few specimens make it out to the mineral collecting market. Collecting in these quarries, such as the Sylvania Minerals Quarry, is limited to a few sanctioned field trips per year. This means only a small fraction of specimens survive the mining process, and even fewer become available for purchase by collectors.

This calcite crystal is a pristine representative of the calcites that occur in the Sylvania Minerals Quarry. It showcases several of the most sought-after features: rich golden coloration, an almost rounded rhombohedral form, crisp edges, and stepped growth along the faces. It has an appealing waxy luster that catches light beautifully and highlights the intricate surface texture. Specimens from this locality of this size and quality are not easy to come by!