Ruby Jewelry Gemstones

Ruby Jewelry Gemstones Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissonite falling somewhere in between corundum (ruby) and diamond in hardness. Ruby is α-alumina (the most stable form of Al2O3) in which a small fraction of the aluminum3+ ions are replaced by chromium3+ ions. Each Cr3+ is surrounded octahedrally by six O2- ions. This crystallographic arrangement strongly affects each Cr3+, resulting in light absorption in the yellow-green region of the spectrum and thus in the red color of the gem. When yellow-green light is absorbed by Cr3+, it is re-emitted as red luminescence.

This red emission adds to the red colour perceived by the subtraction of green and violet light from white light, and adds luster to the gem's appearance. When the optical arrangement is such that the emission is stimulated by 694-nanometer photons reflecting back and forth between two mirrors, the emission grows strongly in intensity. This effect was used by Theodore Maiman in 1960 to make the first successful laser, based on ruby. All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form, with heat treatment being the most common practice. However, rubies that are completely untreated but still of excellent quality command a large premium. Some rubies show a 3-point or 6-point asterism or "star".

These rubies are cut into cabochons to display the effect properly. Asterisms are best visible with a single-light source, and move across the stone as the light moves or the stone is rotated. Such effects occur when light is reflected off the "silk" (the structurally oriented rutile needle inclusions) in a certain way. This is one example where inclusions increase the value of a gemstone. Furthermore, rubies can show color changes — though this occurs very rarely — as well as chatoyancy or the "cat's eye" effect This article is about the mineral. For other uses, see Ruby (disambiguation). Ruby Natural ruby crystals from Winza, Tanzania General Category Mineral variety Chemical formula aluminium oxide with chromium, Al2O3:Cr Identification Color Red, may be brownish, purplish or pinkish Crystal habit Varies with locality. Terminated tabular hexagonal prisms. Crystal system Trigonal (Hexagonal Scalenohedral) Symbol (−3 2/m) Space Group: R-3c Cleavage No true cleavage Fracture Uneven or conchoidal Mohs scale hardness 9.0 Luster Vitreous Streak white Diaphaneity transparent Specific gravity 4.0 Refractive index nω=1.768 – 1.772 nε=1.760 – 1.763, Birefringence 0.008 Pleochroism Orangey red, purplish red Ultraviolet fluorescence red under longwave Melting point 2044 °C Solubility none Major varieties Sapphire Any color except red Corundum various colors Emery Granular A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide).

The red color is caused mainly by the presence of the element chromium. Its name comes from ruber, Latin for red. Other varieties of gem-quality corundum are called sapphires. The ruby is considered one of the four precious stones, together with the sapphire, the emerald, and the diamond. Prices of rubies are primarily determined by color. The brightest and most valuable "red" called pigeon blood-red, commands a huge premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Cut and carat (weight) are also an important factor in determining the price http://en.wikipedia.org/wiki/Ruby

Obsidian jewelry Gemstones Obsidian

Obsidian jewelry Gemstones Obsidian Obsidian jewelry obsidian cocktail ring Gemstones Obsidian Obsidian gives a clear insight into problems

Color: Obsidian is usually black. Other colors include: brown, gray, red, blue and green, clear, orange, yellow.

Description: Obsidian is a natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. Obsidian is extremely rich in silica (about 35 to 80 percent) and is low in water. Obsidian is made of the same minerals as granite but cooled so quickly that they do not have time to crystallize.
Obsidian has a glassy lustre and is slightly harder than window glass. Though obsidian is typically jet-black in color, the presence of hematite produces red and brown varieties, and the inclusion of tiny gas bubbles may create a golden sheen. Obsidian in attractive and variegated colors is used as a semiprecious stone.

The name's origin: Discovered by Obsius in Ethiopia, obsidian is named after him.

Varieties: Black patterned obsidian with greyish-white inclusions which resemble snowflakes is often called snowflake obsidian.

Care and treatment: Obsidian is fairly fragile. Avoid sharp blows as it will crack.

From the stone history: Obsidian has been used for thousands of years for toolmaking. In 1967 archaeologists working at the site of Tlapacoya, southeast of Mexico City, uncovered a well-made blade of obsidian associated with a radiocarbon date of about 21,000 BC.
Sharp shards of obsidian were formed into arrowheads by Indians, who obtained large quantities of obsidian from Obsidian Cliff in Yellowstone National park. The Aztecs used a great deal of obsidian for tools, including sacrificial knives, the eyes of carving of their gods, and even mirrors.
Obsidian is used for dating. Obsidian weathers slowly at a uniform rate, and the thickness of the weathered layer is measured microscopically and gauged against known standards to give a date in years.
Obsidian has also been used for jewelry for centuries.
Mystical power: Obsidian is often used for gaining clear insight into problems. Obsidian stabilizes and is a chastiser.

Deposits: The obsidians of Mount Hekla in Iceland, the Eolie Islands off the coast of Italy, and Obsidian Cliff in Yellowstone National Park, Wyoming, U.S., are all well-known occurrences. Obsidian is also found in Hawaii, Japan and Java. Dark pieces found in Arizona and New Mexico are called Apache Tears.

Gemstones Agate

Gemstones Agate Agate jewelry Agate brings stability to your life.
Color: Agate comes in most colors. Agates range from transparent to opaque in a variety of beautiful colors. It presents various tints in the same specimen. The stones can be artificially stained to produce combinations of color more vivid than those found in the natural state.

Description: SiO 2 Agate is a semipellucid crystallized quartz, consisting of banded or with branching inclusions chalcedony . Physical properties of agate are in general those of quartz.
Agate has irregular, sometimes circular bands of color and often replaces fossil wood. Many fossils are agatized material where the original organic substance has been replaced by agate while retaining the original structure. Agates are identical in chemical structure to jasper , flint, chert, bloodstone , and tiger-eye , and are often found in association with opal .
The colorful, banded rocks are used as a semiprecious gemstone and for making mortars and pestles. One will often see these in beads, agate pendants and necklaces.

The name's origin: Agate derives its name from the Greek "Agate??" - happy.
According to another theory the word Agate comes from the Greek name of a stone found in the Achates River in Sicily, now known as the Drillo River, which still remains a major source of this stone.

Birthstone: Agate is the birthstone of Taurus (Bull): April 20 - May 20.

Wedding anniversary: Agate is the anniversary gemstone for the 12th year of marriage. Moss Agate is the anniversary gemstone for the 14th year of marriage.

Varieties: There are several types of agate. Varieties include Blue, Blue Lace, Crazy Lace, Green, Indian, Moss, Tree and Wood. The Moss agate or mocha stone contains visible impurities in the form that resemble moss.

Care and treatment: Agate will chip and crack rather easily though it has a hardness rating of 7. As with all gems, protect agate from scratches and sharp blows. Avoid sudden temperature changes and household chemicals.

From the stone history: Agate was discovered with the Stone Age man in France 20,000-16,000 BC. The Egyptians used it prior to 3000 BC. Agate was highly valued by ancient civilizations. Said by the ancients to render the wearer invisible.
The agate-working industry grew up centuries ago in the Idar-Oberstein district of Germany, where agates were abundant.
Cameos are cut from stones, such as onyx or agate, where different colors occur in layers. The background material is cut away, leaving the cameo design in relief.
Agate is one of the gemstones, that used in commesso , also called florentine mosaic. Commesso is a technique of fashioning pictures with thin, cut-to-shape pieces of brightly colored, semiprecious stones, developed in Florence in the late 16th century. The stones most commonly used are agates, quartzes , chalcedonies , jaspers , granites, porphyries, petrified woods, and lapis lazuli . Commesso pictures, used mainly for tabletops and small wall panels, range from emblematic and floral subjects to landscapes.

Healing ability: Agate is cooling stone, it reduces fever, quenches thirst, beneficial in stomach area. It quiets the pulse and heart throbs and insures good health and a long and prosperous life.
Botswana Agate: Use with high-pressure oxygen therapy.
Fire Agate: Master healer with color therapy, enhances all essences. It grounds and balances, binds sexual & heart chakra, burns energy.

Moss Agate: Emotional priorities, mental priorities; circulatory, pancreas & pulses, blood sugar balance, agriculture.