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Oxide (Chalcedony)

Jasper

SiO₂

About Jasper

Jasper is an aggregate of microgranular quartz and/or chalcedony and other mineral phases, and is an opaque, impure variety of silica. The name implies "spotted or speckled stone". It breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for vases, seals, and snuff boxes. The specific gravity of jasper is typically 2.5 to 2.9.

Formation & Geology

Jasper is essentially chert (sedimentary rock) that owes its red color to iron(III) inclusions. Patterns arise during the consolidation process, forming flow and depositional patterns (sediment) or through fracturing (breccia). It often forms in the cracks of volcanic rocks or as sedimentary deposits on the sea floor that have been uplifted.

Physical Characteristics

Jasper is an opaque rock of virtually any color stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica rich sediment or volcanic ash. Hydrothermal circulation is generally thought to be required in the formation of jasper.

Varieties of Jasper

Jasper is a collector's dream because there are thousands of named varieties. **Red Jasper** is the most common, colored by iron. **Ocean Jasper** (from Madagascar) features orbicular (circular) patterns. **Bumblebee Jasper** is actually a volcanic rock containing sulfur (yellow) and manganese (black). **Mookaite Jasper** is a colorful Australian radiance of purple, red, and yellow.

Historical Significance

Jasper is one of the oldest known gemstones. It is mentioned in the Bible as one of the stones in the High Priest's breastplate. In the ancient world, Red Jasper was a favorite for amulets and seals because it was believed to stop bleeding and protect warriors in battle. The Babylonians and Assyrians used it for cylinder seals.

Care & Identification

Jasper is tough. With a hardness of 7, it is excellent for tumbling, carving, and daily-wear jewelry. It takes a high polish but is strictly opaque. If you shine a light through the edge of a stone and light comes through, it is likely agate, not jasper.

Colors & Varieties

Red, yellow, brown, green, multicolored

Key Properties

Completely opaque
Microcrystalline quartz
Spotted or patterned
Contains up to 20% foreign material
Vitreous to dull luster
Conchoidal fracture

Uses & Applications

Cabochons and beads
Carvings and sculptures
Tumbled stones
Inlay work
Historical seals

Where to Find

India
Russia
Egypt
Madagascar (Ocean Jasper)
Australia (Mookaite)
United States (Oregon, Idaho)
Brazil

Frequently Asked Questions

Is Bumblebee Jasper real Jasper?

Technically, no. Bumblebee Jasper is a rock composed of volcanic matter, anhydrite, hematite, sulfur, and arsenic. It contains no quartz, so it is not a true jasper. It is soft (hardness 4) and should be handled with care due to the toxic arsenic and sulfur content.

What is the most valuable Jasper?

While most jasper is affordable ($1-$5 per carat), rare landscape patterns (Picture Jasper) or specific localities like "Morrisonite" or "Imperial Jasper" from Mexico can command high prices. Ocean Jasper from Madagascar is also increasingly valuable as the veins are mined out.

Does Jasper break easily?

No, jasper is very tough. Unlike crystals that have cleavage planes (like diamond or topaz), jasper is a massive aggregate. It resists breaking and chipping very well, making it perfect for bracelets and rings that get bumped often.

What is Bloodstone's relation to Jasper?

Bloodstone is often classified as a variety of Jasper (Green Jasper with red hematite spots) or sometimes as Chalcedony. The line between Agate, Jasper, and Chalcedony is often blurry, but Bloodstone is generally opaque like Jasper.

How do I polish Jasper?

Jasper is a favorite for rock tumblers. It takes a very high, glass-like polish using cerium oxide or aluminum oxide grit. It is hard enough to polish well but not so hard that it takes forever.

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