Rock Identifier
Red Jasper (possibly) (Jasper (a variety of Chalcedony, SiO2)) — Mineral
Mineral

Red Jasper (possibly)

Jasper (a variety of Chalcedony, SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Typically reddish-brown to dark brown, can be black, yellowish, or green with translucent to opaque varieties. Luster: Vitreous to resinous. Crystal Structure: Not applicable as it is amorphous (lacks a defined crystal structure). Cleavage: None (due to its amorphous nature).…

Hardness
6
Luster
Vitreous to resinous
Identified More mineral

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Typically reddish-brown to dark brown, can be black, yellowish, or green with translucent to opaque varieties. Luster: Vitreous to resinous. Crystal Structure: Not applicable as it is amorphous (lacks a defined crystal structure). Cleavage: None (due to its amorphous nature). Specific Gravity: 2.3-2.9.

Formation & geological history

Red jasper forms as a primary mineral in various geological environments, often as volcanic fill, in hydrothermal veins, or as sedimentary deposits. It is commonly found in formations where silica-rich waters have percolated through rocks, depositing cryptocrystalline quartz with iron inclusions (which give it its red color). Its geological age can vary widely depending on the specific deposit, ranging from hundreds of millions to thousands of years old.

Uses & applications

Red jasper is widely used as an ornamental stone, cabochon, and in sculptures due to its attractive colors and ability to take a good polish. It's popular in jewelry for beads and tumbled stones. In construction, larger pieces might be used for decorative facings, though this is less common than for harder stones. It's often collected for its aesthetic appeal and variety of patterns.

Geological facts

Jasper is a cryptocrystalline variety of quartz, meaning its crystals are too fine to be seen even with a microscope. It is known for its wide array of colors and patterns, often found in stripes, spots, or flames. Historically, jasper has been used since ancient times for tools, seals, and ornamental objects. It is often associated with properties of strength, courage, and grounding.

Field identification & locations

To identify jasper in the field, look for its characteristic opaque appearance and often earthy, rich color palette. It tends to have a smooth, waxy feel when polished and breaks with a conchoidal fracture (like glass). It can be found worldwide, with significant deposits in the USA (e.g., Oregon, California, Idaho), India, Russia, Brazil, and Egypt. For collectors, look for pieces with interesting patterns or vibrant colors. It will scratch glass, but not corundum.