Bloodstone is a dark green mineral with distinctive red or reddish-brown spots. Its appearance, resembling drops of blood, gives the stone its common name. Also known as heliotrope, it is a microcrystalline variety of quartz called chalcedony.
Geological Formation and Environment
Bloodstone typically forms through geological processes involving silica-rich fluids. Composed primarily of silicon dioxide, its deep green coloration comes from inclusions of various iron-bearing minerals, such as chlorite, epidote, or amphibole.
The characteristic red spots are due to iron oxide, most commonly hematite, integrated into the chalcedony matrix as it crystallizes. Bloodstone is often found in geological settings associated with volcanic or metamorphic activity, where silica-rich solutions percolate through existing rocks. It can occur in hydrothermal veins, within sedimentary beds, or as alluvial deposits in riverbeds and gravels. Conditions of temperature, pressure, and mineral composition contribute to its unique appearance.
Primary Global Sources
India is a prominent source of high-quality bloodstone, with significant deposits in Gujarat, particularly around Cambay (Khambhat). Indian bloodstone is known for its intense green color and vivid red spots. The Deccan Traps region has been a major source for centuries, producing vibrant, beautifully patterned specimens.
Brazil also contributes significantly to the global supply. Deposits are in states like Minas Gerais, Espírito Santo, and Bahia. Brazilian bloodstone is recognized for its vibrant green hue and distinct red inclusions. Australia also yields notable bloodstone, with deposits across the country, particularly in Victoria. Australian bloodstone can display a darker, more bluish-green base with smaller or more scattered red markings.
Other Notable Occurrences
Beyond the primary sources, bloodstone is found in several other regions around the world, though often in smaller quantities or with less commercial significance. In the United States, deposits have been identified in various western states, including California, Oregon, Washington, Nevada, Wyoming, Idaho, and Montana. American bloodstone may present a darker green with less vibrant red flecks compared to material from India or Australia.
Other countries with known bloodstone occurrences include China, Russia, and several African nations. Madagascar, South Africa, and Namibia are recognized for African bloodstone, which can sometimes exhibit additional color variations like brown or yellow inclusions alongside the red spots. Historically, parts of Europe, such as Germany, have also yielded bloodstone.
Identifying Bloodstone in its Natural State
In its natural, unpolished state, bloodstone typically appears duller and may have a rough texture, unlike the waxy or vitreous luster seen in cut and polished specimens. The most recognizable feature is its dark green color, which can range from a deep forest green to a slightly bluish-green. Scattered throughout this green matrix are irregular red to reddish-brown spots or splatters, caused by iron oxide inclusions.
These red markings are usually randomly distributed rather than forming perfect shapes. Bloodstone is generally opaque, though high-quality specimens might show slight translucency at very thin edges. It has a hardness ranging from 6.5 to 7 on the Mohs scale. In the field, bloodstone is often found as veins, nodule fillings within sedimentary or volcanic rocks, or as water-worn pebbles in river gravels. A simple authenticity test is that real bloodstone feels cool to the touch and warms slowly.