What we call ruby, is the red variety of the mineral Corundum. Other colours are named Sapphire. It wasn’t until the 19th century that ruby and sapphire were brought together under the same mineral group . Prior to this it was believed that red spinel and garnet were also ruby . The large, red stone in the Imperial State Crown, called the “Black Prince’s Ruby”, is in fact a polished (but uncut) spinel.
Second only to diamond Corundum is the hardest of all minerals and this contributes to the cut and polished stones luster and beauty.. Inclusions are common but are not indicative of lesser quality but show the difference between a natural and synthetic stone . The type of inclusions can also give an indication of where the stones are from. Included rutile needles give a cat’s eye effect or the very desirable six-rayed star effect (asterism).
Properties
Mineral group: Corundum
Chemistry: Al2O3
Colour: Red-Pinkred (other colours are classified as sapphire)
Crystal system: (Trigonal) hexagonal prisms or tables.
Mohs Scale hardness: 9
Refractive index: 1.762-1.778
Birefringence: -0.008
Specific gravity: 3.97-4.08
May be confused with
Almandite, pyrope, spinel, topaz, turmaline and zircon. There are also many imitations and simultants wich are false rubys. More is the commonly occuring syntetic ruby. They can be very difficult to separate from natural ruby.
Treatments
Heat treatment of rubies is common and accepted. The most common treatment nowdays are Leadglas/Fluxhealing metods. Material with Flux/Pb-glass treat. is natural real Ruby´s but would in some case, without this treatment not be resonable gem quality. However this treatment can in the other hand give more strong material because of healed cracks and simmilar. Cheap, beutiful and mostly very suitable in all kind of jewelry. Read/learn more about this treatment in our blog here http://riddgem.se/blogg/
Instruments suitable for ID
Polariscopes to determine crystal form and separate from a number of other possible gemstones. Garnet have cubic crystal and will be easily separated.
Microscope / Loupe to examine inclusions. The most importent way to separate from syntetic ruby. Genuine natural ruby have broken growth lines compare to syntetic ruby having slightly curved straight lines. Also inclusions is importent to examine in this case.
The refractive index and density are very important data which are determined by refractometer and hydrostatic weighing.
Known deposits
Known deposits in Sri Lanka, Thailand, Vietnam och Burma. The largest deposit and production this days from Madagascar.
Miscellaneous
Read/learn more about Ruby
Gemstone Guides & Knowledge
Read more about Ruby on RIDDGEM Blog
Watch movies and Shorts about Ruby on RIDDGEM YouTube
Ruby – Healing Properties
Ruby is a powerful stone of passion, strength and life energy. It has been used for thousands of years as a symbol of love, courage and vitality. Ruby helps to strengthen willpower, increase motivation and create a deep sense of inner power.
Read/learn more about Ruby – Healing Properties
