Agate is supposed to be a cooling stone as it reduces fever, quenches thirst, quiets the pulse and ensures good health. Agate is also believed to cure insomnia, ensure pleasant dreams, protect from danger, promote strength, healing and a bold heart. Wearers become temperate, continent and cautious.

Formed in a unique way, the main conditions necessary for agate formation are the presence of silica from devitrified volcanic ash, water, manganese, iron and other mineral oxides that form the bands and inclusions.

Agate is a fine-grained fibrous variety of Chalcedony Quartz and comes in many different forms ranging from transparent to opaque. Varieties include Blue, Blue Lace, Crazy Lace, Green, Indian, Moss, Tree and Wood. And the most popular forms are: Blue lace agate which has swirly white bands in a blue background; moss agate with its moss-like pattern; fire agate a brown-bodied stone containing yellow, green and orange spots, with an iridescent shimmer like opal.

The value of the agate mainly depends on the variety of the agate. Most agates are in the low price range but some stones, carvings and unique pieces command higher prices.

A clear to opaque stone Apatite comes in many colors, including green, yellow, blue, violet and yellow-green. Cat's Eye Apatite stones are also known. Apatite is found in: Brazil, Russia, Myanmar (Burma), Sri Lanka (Ceylon), Canada, East Africa, Sweden, Spain and Mexico. Apatite is best used in making earrings and pendants as it is quite soft and exhibits a pale translucency.

Apatite is actually three different minerals depending on the predominance of either fluorine, chlorine or the hydroxyl group: Calcium (Fluoro, Chloro, Hydroxyl) Phosphate. These ions can freely substitute in the crystal lattice and all three are usually present in every specimen although some specimens have been close to 100% in one or the other.

The cost of the stone depends on the intensity of the color. The best stones will be almost a neon greenish blue with clean clarity. Stones over 1 carat in size are rare and will command higher prices.

A series name for a group of four related minerals Axinite is composed of several different ions (Ca2 (Mn, Fe, Mg) Al2 (BO3OH)(SiO3) 4). Though all have the same structure they are different in terms of chemistry. They are named for their respective enrichment in iron, magnesium and manganese; or iron manganese intermediate - tinzenite. The minerals differ slightly in color and specific gravity. Ferro-Axinite is rich in iron and reddish brown to black in color with an average Specific Gravity of 3.31, while Magnesio-Axinite, is magnesium rich, pale blue to gray in color and has an average Specific Gravity of 3.18. Manganaxinite is manganese rich, yellow-orange in color, with a Specific Gravity of 3.32, while Tinzenite is iron and manganese intermediate, predominantly yellow, with a Specific Gravity of 3.37.

Manganaxinite found at Franklin, New Jersey has an attractive yellow-orange color and a red fluorescence, a special characteristic that is not seen in the other Axinites.

Despite the differences, most collectors refer to them as simply Axinite. Good specimens of Axinite can have an extraordinary color and crystal habit and a nice luster that make them popular for collectors.

Alexandrite is a form of the mineral Chrysoberyl and appears as cats eye or as a faceted gem with an unusual green tint. Discovered in 1830, Alexandrite appears medium to bluish green when seen under sunlight or fluorescent light and violet red when seen under candlelight or bright light. This property of color change is seen in many gemstones besides Alexandrite such as Sapphire, Garnet, Apatite, Tourmaline etc. However the extent of color change exhibited by the various gemstones varies and is the most extreme ever seen in natural gems.

As these stones exhibit different colors under different lights they are best used in making earrings, which will exhibit the color change property of Alexandrite very distinctly. Since it is a hard stone, rings made of this gemstone are also very popular. Fine quality Alexandrite cats eyes are also used to make signet rings as these are semi-transparent with a distinct white eye.

The major source of Alexandrite is found in the state of Minas Gerias, Brazil. In 1987, the largest deposit of Alexandrite was found at the Lavra de Hematita mine. And in 1993, another source was found near the Tanzania-Mozambique border. However the original Russian source is nearly depleted due to the popularity of this gemstone.

The value of this gemstone mainly depends on the degree of the color change. The lower quality stone will exhibit a lesser change of color while retaining the original green color or may even appear brown under bright light. The evaluation of Alexandrite should thus be made in a dark room under a light source.

Ammonite, the fossilized remains of a squid-like creature found over 65 million years ago, is rarer than a diamond. Ammonites were found in the oceans preying on the smaller forms of marine life from the Paleozoic era to the end of the Cretaceous era. They were abundant in all the oceans for nearly 330 million years until they became extinct.

Similar to the present day Squid, Octopus and Nautilus, the Ammonites were Cephalopods, which could swim due to their unique shell construction, which was divided into air chambers. The air in these chambers allowed the animal to float and move around.

Though Ammonite fossils are found in every continent, the ones found in Alberta, Canada are treasured since they exhibit the most vibrant colors. Some of them also display intricate patterns. Found in various sizes and colors, the value of Ammonites depends on its size, shape, color and overall appearance. And every Ammonite is unique in color and pattern; the rarest of which exhibits three or more colors and belongs to the AA grade. In Ammonites, the ones displaying one or more colors are graded as A, whereas the ones with indistinct colors are said to belong to the B grade. Ammonites have a Hardness of 5 - 6 on the Moh’s Scale, a Refractive Index of 1.52 - 1.67 and a Specific Gravity of 2.8.

Mineralized fossils of Ammonite were found at St. Mary's River in Alberta in 1908, by a member of the National Geological Survey team. However it was not until 1981 that good quality Ammonite was discovered, thus making it commercially viable. Thus in 1981 Ammonite was officially recognized as a gemstone by the International Commission of Colored Gemstones.

The shell of the Ammonite was similar to the horns of the ancient Egyptian god of life and reproduction, thus it was named Ammon after this deity. Similarly the North American Blackfoot Tribe also know Ammonite as the Buffalo Stone, the stone that signifies wealth and abundance. The story has it that during a harsh winter, a famine hit the people. It is believed that the Great Goddess directed the Princess to find the brilliantly colored gemstone, which saw them through the harsh winter. Thus they believe it to be a gift from the gods. The Navajo tribesmen also used it as a healing stone.

Apophyllite is the name of a group of three minerals, which have similar chemical and physical properties. Of the three minerals namely Fluor-Apophyllite, Hydroxy-Apophyllite, and Natro-Apophyllite, the former is the most common and is also simply referred to as “Apophyllite”. It is the most colorful of the group and occurs in white, green, yellow, violet or colorless specimens. Some of them also fluoresce yellow or pale green under uv light.

Apophyllite a very popular stone among mineral collectors is not well known among the public. It has a Hardness of 4.5 - 5.0 on Moh’s Scale and a Specific Gravity of 2.3 - 2.4. The name Apophyllite is derived from the Greek word, which means ‘to flake apart’ due to the reason that this crystal flakes when heated due to water loss.

Hydroxy-Apophyllite is also known but they generally lack color. They are found at Ore Knob Mine, Jefferson, North Carolina. The rarest of the three Natro-Apophyllite is either yellow, brownish yellow, brown or colorless and is found in Okayama, Honshu, Japan.

Apophyllite is quite popular among the collectors because of its beautiful colors, luster and crystal formation. The green form of Apophyllite especially is believed to bring about love and joy and beneficial in treating asthma, colon and bladder disorders.

Azurite has been named after the Arabic word ‘Azul’ which means blue. Named after its deep blue coloring, Azurite has also been used as a pigment for years. Used in the make-up of eyes by the ancient Egyptians, it is used in the manufacture of good quality artist’s paints even today. Azurite is chemically a Copper Carbonate Hydroxide Cu3(CO3)2(OH)2 compound and its intense coloring is due to the presence of copper, which is a coloring agent and the manner in which it combines with the carbonate groups (CO3) and hydroxyls (OH).

Azurite alters chemically to form Malachite, which is green in color and the two varieties are found within one stone to create beautiful blue-green colored patterns. Not only do Malachite and Azurite occur together, they also have very similar formulae and thus Malachite can replace Azurite, so as to make a pseudomorph – an exact copy of an Azurite crystal except that it is green in color. Azurite mixed with dark red colored Cuprite also forms the rare mixture known as “Bluebird”. All three – Azurite, Azure-Malachite and Bluebird are used as gems.

The demand for Azurite is very high as it is very popular among the collectors. The blue stone is cut into beads and cabochons and the larger masses are cut into ornamental pieces. Azure-Malachite too is cut into beads and cabochons.

Azurite is brittle and transparent if present in thin crystals, otherwise the stone is translucent to opaque. It has a hardness of 3.5 – 4 on the Moh’s Scale and a specific gravity of 3.7+. As it is not very hard it can be easily scratched with a knife.

The largest crystals till date have been found from Tsumeb, Namibia. Some of the great works made from this stone are also part of the collection in the Hermitage Museum, Moscow. Good fine quality specimens of Azurite are found in a number of places such as: Chessy (France), Laurium (Greece), the Black Forest (Germany), Cornwall (England), Burra Burra (South Australia), Broken Hill (New South Wales, Australia), San Carlos Mine (Mazapil, Zacatecas – Mexico) and in Utah, New Mexico, various places in Arizona and Bisbee, Cochise Co. (USA).

Azurite-Malachite is sometimes coated with colorless wax or impregnated with hardening agents to improve its durability and appearance. Linarite stones are also mistakenly sold as Azurite as they both occur in the same locations and sometimes even resemble each other. However they can be distinguished on the basis of some physical properties.

It is believed that Azurite clears the mind of its subconscious thoughts and helps people to understand their fears and desires better. Some also believe that wearing this mineral can make you more creative and enhance the intellectual receptivity. Others believe it to have medicinal value and use it to heal throat, spleen and spine disorders. And one of the most common uses of this mineral is in easing the rheumatic pain, maybe because of its close association with copper.

Amethyst a form of Quartz is one of the most common substances found on earth. Small amounts of iron and aluminum turn clear ordinary quartz into amethyst. Amethyst as well as other forms of quartz are piezoelectric thus they are widely used in important electronic applications.

Amethyst has been popular as a gem since the Pre-Roman times. The intense color and easy availability of Amethyst has ensured its high popularity throughout the millennium. The Greeks believed that amethyst gemstones could prevent intoxication, while the medieval European soldiers wore amethyst amulets in battles for protection. The high-grade quality amethyst mined today mostly comes from Uruguay, Southern Brazil and Africa.

Amethyst is available in colors ranging from pale to dark violet. The finest Amethysts have a medium dark violet coloration with a strong secondary red color. And darker shades of Amethyst may display slight color fluctuations under different light sources. All qualities of Amethyst are available in various different sizes and shapes. Though light grade Amethyst has a low price per carat, the finest quality stones are also very reasonably priced.

Amethyst is ideal for all types of jewellery such as earrings, necklaces and rings and cut in a variety of shapes such as Antique, Baguette, Marquise, Octagon, Oval, Pear, Trilliant and some other fancy cuts in sizes ranging from a few points up to several carats.

Discovered in Spain, Andalusite is named after the province Andalusia. It is a polymorph with two other minerals, namely kyanite and sillimanite, with whom it shares the chemical nature but differs in its crystal structure. Andalusite which contains black / brown clay and / or carbonaceous material in its crystal inclusions arranged in regular symmetrical shapes, usually in the form of a cross of 'X' and is called "Chiastolite"

Andalusite is pleochroic in nature that is it displays different colors when seen in different directions, Thus, it appears as a white, red, brown, orange and green colored stone. Though it is mined in Brazil and Sri Lanka, Andalusite is also found in Andalusia, Spain; Austria; California, USA and China.

With a hardness of 7.5 on the Moh's Scale and a Specific Gravity of 3.15 +, Andalusite has a vitreous luster and its crystals are transparent to translucent. It is also found in association with other minerals such as cordierite, biotite, feldspars, quartz, kyanite and sillimanite.

While cutting Andalusite, the cutters try to orient the gemstone so as to get a pleasing mixture of colors namely, orangey brown, yellowish green and gold colors, thus exhibiting patterns of color dancing around its facets. Depending on the skills of the cutter, in rectangular variations one can see superior color play, whereas in round cuts the colors tend to blend together.

It has been often referred to as a 'poor man's alexandrite' because it offers color play at affordable prices. However one should remember that it features all the colors at the same time whereas alexandrite changes colors from green to red in different sources. Thus it is a gemstone that offers a lot of impact inexpensively. And is frequently used in men's jewellery due to its color and durability.

Made of beryl, Aquamarine is a hard gemstone. For centuries it was believed to contain oceanic energy and thus was worn as amulets by sailors, who believed that the stone would give them power to overcome even the most powerful storm while at sea.

Brazil was a major supplier of Aquamarines, but today African nations such as Nigeria and Madagascar also provide a great supply of this stone. It is a good choice for jewellery due to its hardness and is frequently worn as aquamarine rings. However due to its delicate color and clarity they are best when set in earrings and pendants.

As aquamarines are eye-clean, any inclusions in this stone can be easily seen. Aquamarines are available in a variety of sizes and as the size of the stone increases, the color of the stone also tends to intensify.

While evaluating this gemstone one should take into consideration the color intensity and the clarity of the stone. Deep blue colored Aquamarines are rare to find and therefore command higher prices in the gemstone market. However unlike other gemstones, people actually prefer much lighter, crystal clear gemstones to the richer, deeper colored ones.