A slightly opaque calcite cluster coming out of a eye-catching pyrite base. The calcite crystals have clean terminations and edges. You can even see small flecks of pyrite floating inside of the calcite crystals!
Measurements: ~2" tall x 5-1/4" wide x 2-1/2" deep -- Calcite Cluster: ~1-1/2" tall x 2" wide x 2-1/2" deep
Location: Daye, Hubei Pyo, China
Calcite is one of the most common minerals which grows in a wide variety of different shapes, colors and translucencies. The mineral itself actually belongs to a calcite group of "related carbonates" that are "isomorphous" with each other. All members of the group crystalize in triangular formations, have perfect rhombohedron cleavages, and in transparent rhombohedrons, display strong double refractions. Aragonite and Calcite are similar in chemical composition (polymorphs) but are structured differently, with Calcite forming triangular crystallization and Aragonite forming orthorhombic crystals (three axes planes, at unequal lengths, and all three axes 90 degrees to one another. Unique Calcite formations are created inside the caves where calcium rich water penetrates the cavern's limestone enclosure and slowly drips and flows on top of itself, allowing for the formation of unique stalactite and other globular formations to be created. In this slow process, other minerals can intermix with each other, adding to the interest and forming unusual specimens, such as the one displayed.
A golden yellow to brown, widely occurring mineral sulfide, FeS2, Pyrite is used as an iron ore and to produce sulfur dioxide for sulfuric acid. It is also known as Fool's Gold because it resembles gold, even though it is harder (H. 5-6) and a paler yellow. Pyrite is often found in quartz veins, sometimes even with gold. Pyrite crystals are common; it may also occur as grains or in masses. It streaks a greenish black and when tarnished, may resemble chalcopyrite. If struck sharply against steel, pyrite gives off sparks. It is thought that early man carried pyrite to start fires that contributed to his survival. The name itself is derived from the Greek πυρίτης (puritēs), "of fire" or "in fire," from πύρ (pur), "fire.”