Kornerupine is often found in certain gem gravels such as the ones found in Sri Lanka. These deposits, called placers, form behind the rocks and bends of rivers and are enriched in heavy grains as lighter material is carried further down stream. Kornerupine has just enough density with a specific gravity of 3.3 to be deposited with other relatively dense minerals. Many of these minerals are gemstones as well, such as sphene , iolite , sapphire , chrysoberyl , ruby , topaz , garnets , andalusite , diopside , zircon , spinel and others. Kornerupine originates as a regional metamorphic mineral before being eroded downstream.
Color is green, colorless, white, pink, yellow or brown.
Luster is vitreous. Crystals are transparent to translucent. Crystal Habit is typically elongated prisms and as rounded grains in gem gravels. Streak is white. Associated Minerals include quartz , orthoclase , sapphire , chrysoberyl , ruby , topaz , zircon , spinel and other gemstones found in placer deposits.