mineral

Magnetite-rich black sand

Magnetite (Fe₃O₄), likely mixed with other heavy minerals

AI-generated identification · may be incorrect

Very fine, dark brown-black granular material with metallic to submetallic sparkle. Magnetite has Mohs hardness 5.5–6.5, black streak, opaque appearance, cubic crystal structure, and strong magnetism; associated grains may include hematite, ilmenite, garnet, and quartz.

Identified September 9, 2026More mineral →

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Physical properties

Formation & geological history

Likely concentrated placer or glacial heavy-mineral sand, formed by weathering and mechanical sorting of iron-rich igneous or metamorphic rocks. The region near 54.5°N, 122.7°W commonly has glacial and alluvial deposits; age is generally Quaternary for the sediment concentration, though source minerals may be much older.

Uses & applications

Magnetite is used in iron production, dense-media separation, concrete aggregate, pigments, and water treatment. Fine natural concentrates are mainly valued as teaching or collecting specimens.

Geological facts

A strong magnet should attract at least part of the sample; magnetite-rich sand often forms a dark line or clump around a magnet placed beneath paper. It may be mistaken for ordinary black sand or finely crushed industrial material.

Field identification & locations

Separate grains with a magnet, test the streak on unglazed porcelain, and inspect with a hand lens for metallic black grains. Common in stream bars, glacial sediments, and lake or beach placer deposits. A magnetic response confirms magnetite but not a unique locality.