ガーネット

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ガーネットは、近縁種である鉱物が集まったグループで、ほとんどすべての色が揃う宝石です。

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器具類

OVERVIEW

ABOUT GARNET

Red garnets have a long history, but modern gem buyers can pick from a rich palette of garnet colors: greens, oranges, pinkish oranges, deeply saturated purplish reds, and even some blues. Red garnet is one of the most common and widespread of gems. But not all garnets are as abundant as the red ones. A green garnet, tsavorite, is rarer and needs rarer rock chemistries and conditions to form.

Garnet Description

Garnet History and Lore

Birthstones & Anniversaries

Garnet is the birthstone for January and the gem for the second anniversary.

Tsavo Park

Campbell Bridges mined tsavorite garnet in Kenya near Tsavo National Park.

Faberge

The imperial Russian jeweler created intricate jewelry designs for demantoid garnet.

3800 BC

A stylish red garnet bead necklace found in a grave in Egypt is more than 5,000 years old.

FACTS

Mineral: Garnet group

Chemistry:

Almandine- Fe₃Al₂(SiO₄)₃

Andradite- Ca₃Fe₂(SiO₄)₃

Grossular- Ca₃Al₂(SiO₄)₃

Pyrope- Mg₃Al₂(SiO₄)₃

Rhodolite- (Mg, Fe)₃Al₂(SiO₄)₃

Spessartine- Mn₃Al₂(SiO₄)₃

Color: All colors

Refractive index: 1.714-1.888

Birefringence: None

Specific gravity: 3.47-4.15

Mohs harness: 6.5-7.5

TREATMENTS

There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.

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SYNTHETICS

Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.

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IMITATIONS

Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.

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WHY WE LOVE THIS GEMSTONE

1
GEMOLOGICAL CHALLENGE

Figuring out how each new gem garnet fits into the six main mineral species is a challenge for gemologists.

2
Horsetail Inclusions

Horsetail inclusions in green demantoid garnet are one of the few internal features that increase a gem's value.

3
Fire

Due to demantoid garnet's high dispersion, well-cut, fashioned gems display an amazing amount of fire.

QUALITY FACTORS

When deciding which garnet to buy, think of garnets in terms of color.

COLOR

Garnet includes affordable dark red varieties, rare and valuable greens, and many colors in between.

CLARITY

Garnet clarity often depends on garnet type. Red garnets often don’t have eye-visible inclusions.

CUT

Many garnets are cut into standard shapes and calibrated sizes to allow setting into manufactured jewelry.

CARAT WEIGHT

Garnets can be found in all sizes and weights, although some varieties are rare in large sizes.

GARNET QUALITY FACTORS: THE COMPREHENSIVE GUIDE

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RESEARCH

Explore sources, gemological research, and the role of gems in history.

Large Namibian Demantoid Garnet Duncan Pay , Jul 31, 2015

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Purple Pyrope-Almandine Garnet From Mozambique Supharart Sangsawong, Victoria Raynaud, and Vincent Pardieu , Nov 7, 2016

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Update on the Scorpion Tsavorite Mine Tao Hsu and Andrew Lucas , Apr 28, 2016

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Vanadium and Chromium-Bearing Pink Pyrope Garnet: Characterization and Quantitative Colorimetric Analysis Ziyin Sun, Aaron C. Palke, and Nathan Renfro , Feb 1, 2016

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VIEW ALL RESEARCH