• Location: Sulawesi – Indonesia
• Weight: 8.5 g
• Dimensions: 1 - 1.6 cm
• Set of 10 pieces
• DETAILED DESCRIPTION

Grape chalcedony is a relatively recent discovery in the mineral market. The first samples were found in 2016 on the Indonesian island of Sulawesi, specifically in the Manakarra area. Grape chalcedony is a variety of quartz and is characterized by distinctive spherical aggregates called spherulites, which form by precipitation from gelatinous silica-rich solutions (SiO₂). These spherical structures, often up to 1 cm in size, are composed of tightly packed, fine filaments of the same length. Individual spheres are often fused together or to the underlying rock, forming a grape-like cluster, hence the name. Grape chalcedonies are known for their delicate or intense colors, especially purple and green. The purple color is caused by the presence of manganese, while rarer green specimens get their color from other impurities in the rock. The samples can also be covered with tiny quartz crystals, giving them a shiny appearance. They form during low-temperature hydrothermal processes in fractures and cavities in volcanic rocks. This process allows the chalcedony to crystallize in typical botryoidal forms. Like all forms of quartz, grape chalcedony is highly mechanically and chemically resistant, making it a durable material suitable not only for collecting but also for creating jewelry such as pendants or earrings.