Tag: gemstone

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What is Lapis Lazuli?

Lapis Lazuli Stones

Lapis lazuli, or lapis for short, is a deep-blue metamorphic rock. It is used as a semi-precious stone. It has been prized since antiquity for its intense color. The name comes from the Persian word for the gem, lāžward. Lapis lazuli is a rock composed primarily of lazurite, pyrite, and calcite. As early as the 7th millennium BC, people mined lapis lazuli in the Sar-i Sang mines and in Shortugai. It was also mined in other mines in Badakhshan province in modern northeast Afghanistan. Lapis lazuli artifacts are dated to 7570 BC. They have been found at Bhirrana, which is the oldest site of Indus Valley civilisation. Lapis was highly valued by the Indus Valley Civilisation (3300–1900 BC). Lapis beads have been found at Neolithic burials in Mehrgarh, the Caucasus, and as far away as Mauritania. It was used in the funeral mask of Tutankhamun (1341–1323 BC).

Lapis lazuli has been used since ancient times and remains popular today. This gemstone has been prized for its bright, blue color. It is used for inlay and intarsia. It is also used for pigments for cosmetics and paintings. Its eye appeal is irresistible. Today, jewelry is its predominant use.

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Lapis lazuli value is determined almost exclusively by color. A deep, intense, blue with violet tones would be at the apex. Fine grained, uniform specimens can attain a smooth, highly polished surface not seen in lower grades.

Calcite inclusions almost always lower the value. Pyrite inclusions enhance it in the minds of many collectors and jewelry lovers. Although enthusiasts may debate how much pyrite is ideal in lapis lazuli, most would agree on one thing. The stone is better with less calcite. Calcite can appear as streaks or patches within the darker blue. It can also predominate in the mix, giving the rock an overall lighter blue shade.

Polish quality and faceting artistry also affect value.

The ancient Roman natural historian Pliny the Elder admired lapis lazuli for its colors. He called it “a fragment of the starry firmament,” because it is deep blue with twinkling bits of gold. Lapis lazuli (also simply referred to as lapis) is actually a rock. It is composed of lazurite, haüyne, sodalite, and nosean. These are all members of the sodalite group of minerals. (Lazurite itself may be considered a sulfur-rich haüyne).

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Archeologists have found lapis lazuli beads, jewelry, and carvings at numerous sites, some dating as early as 6,000 BCE. The use of this gem material for art and jewelry probably originated in Afghanistan. It spread to Asia, the Middle East, the Mediterranean, and the Roman world. In the Latin-speaking world of classical antiquity, many gemstones called sapphire or sapphirus may have been pieces of lapis. These names mean “blue stone.” In classical antiquity’s Latin-speaking world, many gemstones called sapphire or sapphirus may have been pieces of lapis. These names mean “blue stone

By the end of the Middle Ages, lapis lazuli began to be exported to Europe. It was ground into powder. The powder was made into the pigment ultramarine. Ultramarine was used by some of the most important artists of the Renaissance and Baroque. These artists include Masaccio, Perugino, Titian, and Vermeer. Ultramarine was often reserved for the clothing of the central figures of their paintings. This was especially true for the Virgin Mary. Ultramarine has also been found in dental tartar of medieval nuns and scribes. This might have been due to them licking their painting brushes while producing medieval texts. It was common when working on manuscripts.

Lapis lazuli usually occurs in crystalline marble as a result of contact metamorphism.

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Lapis takes an excellent polish and can be made into jewellery, carvings, boxes, mosaics, ornaments, small statues, and vases. Interior items and finishing buildings can be also made with lapis. During the Renaissance, lapis was ground and processed to make the pigment ultramarine for use in frescoes and oil painting. Its usage as a pigment in oil paint largely ended during the early 19th century. This change occurred when a chemically identical synthetic variety became available.

Lapis lazuli is commercially synthesized or simulated by the Gillson process. This process is used to make artificial ultramarine and hydrous zinc phosphates. Spinel or sodalite, or dyed jasper or howlite, can be substituted for lapis. (1)

Sources

(1) Wikipedia
(2) Photos by Freepik

In My Shop

Multicolor Lapis Lazuli Bracelets

Multicolor Lapis Lazuli Bracelets

$21.00

These Multicolor Lapis Lazuli Bracelets are composed of 8mm Natural Multicolor Lapis Lazuli Beads and elastic cord

SKU: SJDB156
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What is Turquoise?

Turquoise stone

Admired since ancient times, turquoise is known for its distinct color, which ranges from powdery blue to greenish robin egg blue. It’s one of few minerals to lend its name to anything that resembles its striking color.

The word “turquoise” dates back to the 13th century, drawing from the French expression pierre tourques, which referenced the “Turkish stone” brought to Europe from Turkey.

Ancient Persia (now Iran) was the traditional source for sky blue turquoise gemstones. This color is often called “Persian blue” today, regardless of its origin. The Sinai Peninsula in Egypt was also an important historical source of turquoise gems.

The U.S. is now the world’s largest turquoise supplier. Nevada, New Mexico, California, and Colorado have produced turquoise, but Arizona leads in production by value, as well as quality. The stone’s popularity here makes it a staple in Native American jewelry.

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Turquoise is found in arid regions where rainwater dissolves copper in the soil, forming colorful nodular deposits when it combines with aluminum and phosphorus. Copper contributes blue hues, while iron and chrome add a hint of green.

Some turquoise contains pieces of host rock, called matrix, which appear as dark webs or patches in the material. This can lower the stone’s value, although the uniform “spiderweb” pattern of Southwestern turquoise is attractive.

Turquoise is sensitive to direct sunlight and solvents like makeup, perfume, and natural oils. The hardest turquoise only measures 6 on the Mohs scale, which made this soft gemstone popular in carved talismans throughout history.

From ancient Egyptians to Persians, Aztecs and Native Americans, kings and warriors alike admired turquoise for thousands of years. It adorned everything from jewelry to ceremonial masks to weapons and bridles.

Highly esteemed for its striking namesake color and its ancient history, turquoise’s popularity remains timeless. (2)

In My Shop

Natural Turquoise Stone Bead Necklaces

Natural Turquoise Stone Bead Necklaces

$27.00

These Natural Turquoise Stone Bead Necklaces are composed of Natural Turquoise Stone Beads, Natural African Turquoise Stone Beads, gold-plated round spacer beads and toggle clasp

2 in stock

SKU: SJDB098
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Sources

(1) Image by tohamina on Freepik
(2) American Gem Society
(3) Image by Freepik

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What is Citrine?

Citrine Pendant

Citrine is the yellow to red-orange variety of crystalline quartz. Clever marketing and the rise of “earth tone” fashions have made this durable and readily available gem a popular jewelry stone in recent years.

Citrine Stone [2]

In terms of color, at the top end of the scale, you’ll find prime specimens of the most saturated yellow, orange, and reddish tones. Those with less intense color fall into lower value ranges, with pale or smoky stones at the bottom.

There’s no exponential increase in value per carat with increase in size, as larger sizes are readily available. Inclusions will decrease value.

As with any gem material, custom cutting increases value. In many fancy cut or carved specimens, most of the value is due to the artistry of the cutting.

Citrine was once the Rodney Dangerfield of the gem world. Due to its abundance, it would “get no respect,” as it were. In recent decades, this perception has changed, partly because earth-tone jewelry has come into vogue. Home shopping networks have also marketed the various shades of citrine aggressively, with catchy adjectives like “butterscotch” and “whiskey.” Apparently, this has worked. Citrine is now a modern alternative birthstone for November.

Mining actually yields very little citrine. The vast majority of citrine on the market is produced by heating smoky quartz (which produces light to medium yellows) and amethyst (which produces stronger yellows and orange-red to orangey brown shades). Natural stones usually occur in pale yellow colors, often with smoky tones.

Citrine Earring [2}

Citrine as a Jewelry Stone

Citrines make fine jewelry stones. With no cleavage and a hardness of 7, they can be used for any jewelry application. Like most quartz, it’s available in large sizes. Thus, custom gem cutters can easily use this stone for dramatic and intricate cuts.

Citrine’s yellow colors are due to the presence of ferric iron, colors traditionally associated with topaz. Confusion between these gemstones does occur, even though quartz and topaz are distinct gem species.

Misnomers

In the past, people commonly referred to citrine by misleading names, such as “Brazilian topaz,” “Madeira topaz,” and even “topaz quartz.” Unscrupulous vendors can still take advantage of the long association of yellow with topaz to pass off inexpensive citrines as more expensive topaz pieces. For more examples, consult our list of misleading or false gemstone names.

Care

Citrines make durable jewelry stones that require little special care. However, heat-treated stones may fade when exposed to heat. Thus, avoid steam cleaning or boiling your citrine jewelry. Instead, use either ultrasonic cleaning or simply warm water, mild detergent, and a soft brush.

Although usually free of inclusions, citrines with low clarity grades — with liquids, gases, or crystals trapped within them — should be cleaned by hand only. However, any heat-treated citrines are most likely safe to clean in an ultrasonic cleaner. [1]

Sources

[1} International Gem Society
[2] Freepik

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What is Sodalite?

Sodalite

Typically blue, durable, and easy to cut, sodalite is highly desired by hobbyists. Even stones that lack transparency make lovely faceted gems.

The gemstone know as sodalite belongs to the sodalite mineral group, which includes haüyne, lazurite, and nosean. All typically blue, these minerals are actually found in lapis lazuli. That is, lapis is a rock made up principally of these materials. However, sodalite and haüyne can also occur separately and even have their own varieties.

Hackmanite, a sulfur-rich variety of sodalite, shows tenebrescence. When first mined, stones from Canada and Greenland can range from pink to violet. In sunlight, however, they fade to grayish white or white. On the other hand, hackmanites from Afghanistan and Myanmar start white but turn pink or violet in sunlight. Darkness will reverse these effects.

Although both sodalite and lapis can have inclusions of calcite, you can distinguish them by sodalite’s lack of pyrite inclusions. [1}

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Laboratories have synthesized sodalites, but the natural gems aren’t rare, so no real market for them exists. However, sodalites, either natural or synthetic, can simulate other blue gems, such as lapis lazuli. Since lapis lazuli is a better known material, it’s more likely you’ll encounter sodalites offered as lapis gems, either in error or a deliberate effort to mislead.

Other popular blue gem materials, like azurite, lazulite (no relation to lazurite), and turquoise, typically show different shades of blue than sodalite. However, if the colors seem close, these stones react differently to ultraviolet testing.

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Hackmanite

Hackmanite from Dungannon Township, Ontario, Canada will luminesce bright pale pink in shortwave (SW) ultraviolet light. In longwave (LW), it luminesces bright yellow-orange. Stones may turn raspberry red after exposure to SW.

When cut, sodalite may release a hydrogen sulfide (H2S), “rotten egg,” smell due to traces of water and sulfur.

How to Care for Sodalite Jewelry

Sodalites are tough but scratch easily due to their relatively low hardness (5.5-6). Other popular jewelry stones, like quartz and topaz, will scratch them. (So will household dust, over time, with its hardness of 7-7.5). Store any sodalite jewelry separately from other pieces to avoid contact scratches. Use protective settings for ring wear. Necklace and earring use should pose fewer risks. Clean these gems only with a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more recommendations.

Sources

[1} International Gem Society
{2} Image by Rafe Whysall from Pixabay
[3] Nature Stock photos by Vecteezy

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What is Jade?

Jade

Jade is an umbrella term for two different types of decorative rocks used for jewelry or ornaments. Jade is often referred to by either of two different silicate mineral names: nephrite (a silicate of calcium and magnesium in the amphibole group of minerals), or jadeite (a silicate of sodium and aluminum in the pyroxene group of minerals). Nephrite is typically green, although may be yellow, white or black. Jadeite varies from white or near-colorless, through various shades of green (including an emerald green, termed ‘imperial’), to lavender, yellow, orange, brown and black. Rarely it may be blue. Both of these names refer to their use as gemstones, and each has a mineralogically more specific name. Both the amphibole jade (nephrite) and pyroxene jade are mineral aggregates (rocks) rather than mineral species. Nephrite was deprecated by the International Mineralogical Association as a mineral species name in 1978 (replaced by tremolite). The name “nephrite” is mineralogically correct for referring to the rock. Jadeite, is a legitimate mineral species, differing from the pyroxene jade rock. In China, the name jadeite has been replaced with fei cui, the traditional Chinese name for this gem that was in use long before Damour created the name in 1863.

raw jade

Jade is well known for its ornamental use in East Asian, South Asian, and Southeast Asian art. It is commonly used in Latin America, such as Mexico and Guatemala. The use of jade in Mesoamerica for symbolic and ideological ritual was influenced by its rarity and value among pre-Columbian Mesoamerican cultures, such as the Olmecs, the Maya, and other ancient civilizations of the Valley of Mexico.

Jade is classified into three main types: Type A, Type B, and Type C. Type A jade refers to natural, untreated jadeite jade, prized for its purity and vibrant colors. It is the most valuable and sought-after type, often characterized by its vivid green hues and high translucency. Type A jade is revered for its symbolism of purity, harmony, and protection in various cultures, especially in East Asia where it holds significant cultural and spiritual importance. Types B and C have been enhanced with resin and colourant respectively.

In Our Shop

Multicolor Persian Jade Necklaces

Sources

Wikipedia
International Gem Society