Ruby
Ruby is the gemstone variety of the mineral corundum. Ruby is pink to blood-red colored gemstone. It also exit in many shades of red, from Pinkish to purplish or brownish-red. The red color in caused mainly by the presence of the element chromium. Ruby is considered one of the four precious gemstones along with diamond, emerald and sapphire. The name Ruby comes from the Latin word Rubber which means Red. Before 1800, red spinel and the red garnet were also designated as ruby and for that reason the true ruby had sometimes been called an oriental ruby "to avoid the mistaken for rubies.
The ruby is also third largest mineral same as sapphire. Its hardness is 9 on Moh scale.
Different types of inclusion of rubies often indicates the source area. Some rubies show a three-point or six-point asterismop. These rubies are cut into cabochous to display effect clearly. Further rubies also can show color changes though this occurs very rarely as well as chatoyancy or the cat's eye effect.
Deposits
The host rocks of ruby are metamorphie dolomite marbles,gneiss and amphibolite.The yield of rubies from such primary deposits is not economically profitable. Rather,secondary alluvial deposits are worked.Because of its high density,ruby is normally separated through the washing of river gravels,sands and soil, then concentrated and finally picked out by hand.
Some of the most important deposits are in Myanmar,Thailand,Srilanka and Tanzamia. For centuries,the most important have been in upper Myanmar near Mogok. In Srilanka deposits are situated in the South West of the island is the district of Ratnapura. Rubies from these deposits are usually light red to raspberry-red. Other mining Deposits are in Afghanistan,Australia,India,Kenya,Malawi,Nepal,Pakistan, Cambodia, Madagascar, Brazil, Tajikistan, Zimbabwe and Vietnam.
Properties of Ruby
| Species | CORUNDUM |
| Variety | Ruby |
| Chem. Comp. | AI2O3(Aluminium Oxide) |
| Cryst. System | Trigonal |
| Habit | Prismatic |
| Colour | Medium light to dark red slightly purplish - red,orangish - red |
| Cause of Colour | Chromium |
| Transparency | Transparent to opaque |
| Lustre | Vitreous |
| Hardness | 9 |
| S . G . | 3.99 to 4.00 |
| SR / DR | DR |
| Pleochroism | Dichroic (strong to weak), yellowish red to deep red |
| Optic Sign | U - ve |
| R . I . Range | 1.760 - 1.768 to 1.770 - 1.779 |
| Birefringence | 0.,008 to 0.009 |
| Spectrum | 4685,4750,4765,5500,6592,6680,6928,6935,6942 A. |
| Dispersion | 0.018 |
Inclusion
Inclusion in general we can found in Rubies - Crystals,fine silk,colour-Zoning,mica,lameller twinnning.
India - silk,crystals,lameller twinning,mica.
Africa - finger prints,silk,crystals.
Burma - crystals,short rutile needles,fine silk,colour-zoning.
Sri Lanka - long routile needles,zircon halos,defused colour zoning,finger prints.
Famous Rubies
Rosser Reeve Star Ruby - With it rich red color and well - defined star,the 138.72 ct. Rosser Reeves Star Ruby might be the largest and finest star ruby in the world.Ruby is the gem variety of the mineral corundum.The star forms when titanium atoms are trapped within the growing corundum crystal.As the crystal cools, the titanium forms needlelike crystals of the mineral rutile, which orient themselves in three directions.
Peace ruby-A 25 carat (43carat uncut) brilliant stone was found at the end of World War I hence the name. This magnificent ruby was mined in 1919 from Mogok mines. It had an irregular hexagonal shape with a flat apex. The color was amazing perfect red as deep as pigeon’s blood. A beautiful stone with unblemished clarity it was purchased by Indian trader in Burma and cut in Bombay into exquisite flawless appearance.
Edwards Ruby - Named after Major General Sir Herbert Benjamin it was 167 carat Burmese ruby donated by John Ruskin in 1887 to British Museum of Natural History.
Simulant
The simulant of ruby are almandite pyrope garnet,spinel,tourmaline zircon,kunzite bixbite,synthetic ruby,doublet etc.
