6.2" Sphalerite, Quartz, Marcasite & Barite - Oumjrane, Morocco

Sphalerite is a part of the sulfide group and typically exhibits a grey/black appearance due to high concentrations of impurities. In its purest state, sphalerite's chemical composition is ZnS, and can display a gemmy transparent light tan/yellow color. This is one of the few minerals that can form crystals ranging anywhere between gemmy and transparent to opaque and metallic-like. Opaque or cloudy sphalerite tends to be most abundant since iron easily replaces zinc in the process of formation.

About Quartz

Quartz is the name given to silicon dioxide (SiO2) and is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich environments--usually igneous rocks or hydrothermal environments like geothermal waters--at temperatures between 100°C and 450°C, and usually under very high pressure. In either case, crystals will precipitate as temperatures cool, just as ice gradually forms when water freezes. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountain formation: these veins can be hundreds of millions of years old.

About Marcasite

Marcasite is an iron sulfide mineral with the chemical formula FeS2. It is similar to pyrite in both its chemical composition and appearance, but it forms an entirely different crystal structure and is much more reactive to humidity. It is often found within sedimentary rock and hydrothermal deposits, and at one point was used for its sulfur content.

About Barite (Baryte)

Barite is a barium sulfate mineral (BaSO₄) known for its high specific gravity, which makes it unusually heavy for a non-metallic mineral. Typically forming in tabular or bladed crystals, barite can also appear in massive, fibrous, or nodular habits. Its colors range from colorless and white to shades of blue, yellow, gray, or brown, often influenced by trace impurities. Barite commonly forms in hydrothermal veins, sedimentary rocks, and as a gangue mineral in lead-zinc ore deposits. It is widely used in industrial applications, especially as a weighting agent in drilling muds for oil and gas exploration. Its striking crystal formations and vivid hues also make it a popular mineral for collectors.