Where is Ruby found?
Corundum (Al2O3) var. Ruby
Got a photo? Identify rocks instantly with the Rockby app
Open the appRuby occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Ruby
Mogok Valley, Myanmar (Burma)
Historically the most important source of the finest 'pigeon's blood' rubies, found primarily in marble deposits and associated placers.
Montepuez, Mozambique
Currently one of the world's largest and most significant sources of high-quality rubies, found in metamorphic rocks and secondary alluvial deposits.
Thailand (Chanthaburi, Trat)
Known for dark red to brownish-red rubies, often found in basaltic host rocks and alluvial deposits.
Sri Lanka (Ratnapura)
Produces a range of ruby colors, often lighter red to pinkish-red, found in ancient alluvial gravels ('gem gravels').
Tanzania (Winza, Longido)
Winza is known for vibrant red rubies, while Longido produces rubies in zoisite matrix. Both are associated with metamorphic environments.
Madagascar
Various deposits yielding rubies of different qualities and colors, often associated with metamorphic rocks.
Vietnam (Luc Yen, Quy Chau)
Produces high-quality rubies, often found in marble-hosted deposits.
Collecting tips
- Geological Context. Focus on areas known for metamorphic rocks (marbles, gneisses, schists) or certain igneous rocks (basalts, syenites). Alluvial deposits downstream from these primary sources are also excellent places to search.
- Associated Minerals. Look for indicator minerals often found with ruby, such as spinel, garnet, phlogopite mica, graphite, and various feldspars, depending on the geological setting.
- Color and Luster. Rubies will exhibit a distinct red color and a strong vitreous to adamantine luster. Even in rough form, the color should be noticeable. Use a strong light source to observe its brilliance.
- Hardness Test (Caution). While not recommended for valuable specimens, a scratch test against known minerals can help. Ruby (Mohs 9) will scratch quartz (Mohs 7) and topaz (Mohs 8). Do not attempt to scratch other precious gemstones without proper knowledge and tools.
- Specific Gravity. Rubies are relatively dense (3.97-4.05 g/cm³). In alluvial deposits, this density allows them to concentrate in 'heavy mineral' traps.
- Fluorescence. Many rubies, especially those from marble-hosted deposits, fluoresce red under long-wave UV light. This can be a useful identification tool, though not all rubies fluoresce strongly.
Quick Check
- Color:
- Red (pinkish-red to deep 'pigeon's blood' red)
- Luster:
- Vitreous to adamantine
- Streak:
- White
Explore Ruby
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.