Colored Stones 13 Sapphires
very fine quality sapphires
"Burmese" describes sapphires with a slightly violetish blue to blue hue, moderately strong to vivid saturation, and medium to dark tone. Their blue can be more intense and saturated than Kashmir sapphires, but it lacks the velvety luster. They might appear somewhat inky under incandescent light. These are considered ____ ____ sapphires.
Celon and Sri Lanka
"Ce___ and "S___ ________" refer to sapphires that generally have a violetish blue to blue hue, with slightly grayish to strong saturation and light to medium-light tone. The light tone means more light returns to the viewer's eyes, so these sapphires tend to be more brilliant than darker-toned sapphires.
Higher, iron, darker, non-basaltic
"Hi_______ levels of ir_____ make basalt-related sapphires da______ than ___-ba_______ sapphires."
"sapphire", blue, corundum.
"Trade members and consumers often use the single word "sa_______e" to describe the bl____ variety of cor________."
Australia, dark blue commercial-quality
A____ is one of the world's major sources of d____ bl_____ com________l-quality sapphires.
inky
Australian sapphire's blue color is often described as
"Blue sapphire, popular
B___ ______e is one of the most po______r colored stones, especially in the US.
spindle-shaped hexagonal pyramid or bipyramid.
Blue sapphire's most common crystal habit is a(n)
slightly greenish blue and slightly violetish blue
Blue sapphire's pleochroic colors are typically
Thai sapphires, 1980's to 1990's
Blue sapphires from Thailand derive from weathered basalts and are recovered from the gravel of nearby rivers and streams. The rough is often waterworn and well-rounded, with corroded surfaces from contact with molten lava. Typical features of Thai stones are included crystals, uneven color zoning, and slight milkiness caused by concentrations of minute light-scattering particles. Because the stones are usually dark, most Thai sapphires are heat treated.
Australian, inky
Blue sapphires from other basaltic sources are sometimes referred to as "Au________," indicating a dark, i____y color that sometimes appears silky or cloudy.
high iron content.
Blue sapphires that originate in basaltic rock generally have
Kashmir, cornflower, velvety
Considered the finest sapphires, "K______ir" describes co_______r blue sapphires that have a ve_____, violetish blue to pure blue hue, with moderately strong to vivid saturation and medium-dark tone.
color zoning, characteristic.
Cutters must consider col____ zo______, a common sapphire char________c.
untreated, valuable
Fine-quality, un________ sapphires make up a small but extremely va_________ segment of the sapphire market.
Flame fusion, synthesis
Fl____ ______ is the most common sapphire s______ method.
geuda and dhun
Heat-treated g____ and d______ make up a significant portion of the commercial-quality blue sapphire market.
The trade and consumers often apply the single word "sapphire" to the blue variety, using "fancy sapphires" for other corundum colors. However, more accurate descriptions use their individual color names, such as yellow sapphire, pink sapphire, and orange sapphire.
How are sapphires sometimes described in the trade?
Heating to improve color and clarity is by far the most common sapphire treatment. Depending on the starting material and conditions, heat treatment can improve blue color, develop silk to create asterism, partially heal fractures, or remove silk to improve clarity and transparency. In conjunction with beryllium lattice diffusion, heating can also lighten dark material. It's estimated that most blue sapphires are treated in some way. Heating and lattice diffusion are the most common treatments. Other treatments, used more rarely, are cavity and fracture filling with oil, epoxy resin, glass-like materials, or polymers; coating with various substances; and dyeing. As with other colored stones, it's important to disclose all sapphire treatments. Whatever the outcome, the results of heating are stable and durable, and heat-treated blue sapphires typically retain their enhanced effects permanently. Because of this, the practice is commonly accepted and supported by the colored stone market. Treated gems require caution with acids (hydrofluoric), heat (jeweler's torch), and chemicals such as caustic soda, and they shouldn't be subject to ultrasonic or steam cleaning.
How do treatments affect blue sapphire's appearance?
glass and synthetic spinel.
Imitations for sapphires include
2014 - Nigeria, Mambilla Plateau, Gembu and Guroji
Important source of blue sapphires, 100 to 300 carats, all with basalt related, secondary deposit characteristics. Gembu: small and darker, Guroji, Large and lighter crystals. Colors can range from very light to very dark blue, and yellow and greenish hues are not as common. Their clarity ranges from very clean to milky, and they display weak pleochroism.
Yogo Gulch, Montana, xenocrysts, igneous rock lamprophyre
In Y____ ______, Montana, the sapphires are x_______, brought to the surface by rocks unrelated to their formation process. The "carriers" are basalt and a rare type of i_____ _____ called l___________.
The characteristics of Kashmire sapphire, zoning, liquid feathers, liquid films
Kahmire sapphire internal characteristics have, the most widespread, z_____, liq______ fea______s, and flat brownish or yellowish liqu____ ______ms.
1880s.
Kashmir sapphires owe their reputation to a brief period of output in the ________s.
1881 to 1887
Kashmir's most important sapphire production period was from
Madagascar, good- to fine-quality
M______ has become a significant source of g_____d- to f_____-quality blue sapphire.
elongated to tabular, barrel shaped bipyrimids.
Madagascar crystals are well developed, typically
alluvial or placer
Madagascar deposits that are the most economically important are
geuda
Milky, grayish, or brownish corundum that can be treated to a fine blue color is called
velvety appearance
Minute inclusions can give Kashmir sapphires a(n)
heat-treated. appearance.
Most blue sapphires are h____-tr______ to improve their a_____e.
Sri Lanka.
Most fine sapphires over 100 carats are from S____ ______
Sri Lanka
Most fine sapphires over 100 cts. come from
alluvia, abrasions, Ratnapura, Elahera, and Balangoda are the main sapphire mining areas in Sri Lanka.
Mostly al______l. Signs of abr_______s, rutile silk, fluid and solid inclusions, cavities. Artisanal minors. Produce 40 species of gems. The bright appearance of Sri Lankan stones can be due to lower levels of iron and titanium. Unlike stones from other sources, Sri Lankan sapphires tend to be large, yielding most of the market's fine sapphires over 100 carats.
basaltic
Northern Madagascar sapphires tend to be
Australia
Regions associated with basalt-related sapphire include Cambodia, Thailand, Nigeria, and
occur in metamorphic rocks and in the zones around igneous intrusions
Southern Madagascar sapphires tend to
Thailand
T__________ is a major center of the corundum trade, funneling a steady flow of gems from worldwide sources into the consumer market.
Thailand, sapphire, volume and value.
Th_______ is the leading exporter of sap_________ to the United States by vo_____e and va_____.
Sri Lanka, Almost all Sri Lankan sapphire rough is cut within Sri Lanka
The cutters in S___ _______are considered the best at orienting sapphire rough
blue to violetish blue
The most highly valued blue sapphire hues are
velvety blue to violetish blue, in medium to medium-dark tones, with strong to vivid saturation.
The most highly valued blue sapphires are v____ ___ to _____ ______, in medium to medium-dark tones, with strong to vi______ sat-------.
GIA has a masterstone for this regal new term for sapphires
The term "r___ _____e" has become a very popular trade term and enjoys growing recognition among consumers as a desirable blue sapphire color. Generally it has been used to describe a deep, highly saturated blue.
iron and titanium, blue of sapphire.
The trace elements______ and ti_______ cause the bl_____ of sap_______e.
"Kashmir", finest blue sapphires.
The trade term "K________ir" refers to what many consider the f______t bl______ sa_________s.
half
US consumers buy about _______ of the blue sapphires on the world market.
Untreated, premium-quality, tiny
Un______, pr_____-qua______ sapphires—a t_______ percentage of the market—make up the most exclusive and costly market sector.
Color zoning is a common sapphire characteristic. To accommodate color zoning in some sapphires, cutters orient the concentrated color in a direction that offers the best color return. Pleochroism in blue sapphire typically appears as a variation between slightly greenish blue and slightly violetish blue in different crystal directions. When a cutter orients the table facet perpendicular to the optic axis direction, the finished stone's face-up color displays more of the preferred violetish blue and less of the greenish blue hue.
What are sapphire's typical clarity characteristics?
Blue sapphire rough comes from sources all over the world. Kashmir, Myanmar, and Sri Lanka, along with some new Madagascar deposits, produce what are considered the finest-quality blue sapphires on the market. Current sources responsible for the bulk of commercial-quality blue sapphire include Madagascar, Australia, Sri Lanka, and Nigeria. Although supplies from previously important sources like Thailand and Cambodia have dwindled, gems from these locations sometimes come back into circulation through private sales and auctions.Sources with the potential to become significant producers are Montana (US), China, Vietnam, Cameroon, and Laos. In addition, there are countless other locations where blue sapphire has been recovered. With exploration going on all over the world, the next source could be almost anywhere.
What are some past and present sources of blue sapphire?
Because heat treatment alters inclusions, it's difficult to rely on them for identification. And rough from various deposits can look the same, making recognition based on appearance practically impossible. This is especially true for blue sapphires from Kashmir, Myanmar, Madagascar, and Sri Lanka. Often it requires sophisticated laboratory tests, including spectroscopy and extensive chemical analysis.
What are the challenges involved in determining a sapphire's origin?
When the trace elements are iron and titanium, the corundum is blue sapphire. Only a few ppma (parts per million atomic) can cause the color, and the more iron the corundum contains, the darker the blue.
What causes sapphire's blue?
A rough sapphire crystal's shape influences the finished stone's shape and size. Rough sapphire's most common crystal habit is a barrel- or spindle-shaped hexagonal pyramid or bipyramid. As a result, finished sapphires often have deep pavilions. To achieve the best overall color, maintain the best proportions, and retain the most weight possible, cutters focus on factors like color zoning, pleochroism, and the lightness or darkness of a stone.
What factors influence a cutter's fashioning decisions?
Color has the most impact on blue sapphire's value. In standardized color terms, blue sapphire ranges from very light to very dark violetish blue to greenish blue. The most highly valued sapphires are velvety blue to violetish blue, with medium to medium-dark tone. Preferred sapphires also have strong to vivid saturation. Sapphires with these qualities command the highest prices per carat.
What is blue sapphire's most important value factor?
Yogo Gulch
What location supplies sapphires that are probably not heat treated?
aceted blue kyanite looks remarkably similar to sapphire due to their similar color-causing mechanisms, and industry, fashion use lower priced synthetics and imitations which drives comsumer interest in authetic, earth mined stones.
What role do synthetic and imitation blue sapphires play in the market?
Titanium and iron
What trace elements cause blue sapphire's color?
the blue variety of corundum.
When trade members use the single word "sapphire," they are referring to
The United States
Which of the following countries is the biggest market for sapphire?
Madagascar
Which of the following sources emerged in the 1990s as a significant source of good- to fine-quality sapphire?
Yogo Gulch
Y____ ______ sapphires are characterized by small size and saturated blue color and do not require heat treatment.
Ambondromifehy, Northern Madagascar,
basalt-related, primarily dark blue, but also green, greenish blue, yellow and greenish yellow.
In 1998, near Ilakaka, southern Madagascar
began yielding blue and pin sapphire. It had a road, led to better infrastructure. Population went from 100 to 40, 000
distinct Kashmir characteristics of sapphires, color zoning, zircon, parmasite, tourmaline,
distinct Kashmire sapphire characteristics distinct col___ zo_____g, included zir____, but included parmasite and tourmaline have not been seen in other regions' sapphires. But the tourmaline and parmasite occur rarely
Andranondambo in southeastern Madagascar
fine quality metamorphic type blue sapphires from the mid 1990's
in 2012, near the town of Didy, northeaster Madagascar
source of blue sapphires appeared and launched a rush.
