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Peridot

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About peridot - History and Introduction

Historical values 2005 - 2016

Color

Color Description; Occurrence

1 ct.

3 ct.

5 ct.

10 ct.

30 ct.

071 - medium dark yellowish Green; very slightly greyish

Alternative name, occurrence category: Chrysolite, Olivine. Common

46.60

60.08

73.56

107.27

242.11

077 - medium slightly yellowish Green; very slightly greyish

Alternative name, occurrence category: Chrysolite, Olivine. Common

74.94

96.63

118.32

172.54

389.40

068 - medium yellowish Green; very slightly greyish

Alternative name, occurrence category: Chrysolite, Olivine. Common

51.93

66.96

81.99

119.56

269.84

065 - medium light yellowish Gren; very slightly greyish

Alternative name, occurrence category: Chrysolite, Olivine. Common

32.65

42.10

51.55

75.17

169.66

About Peridot - History and Introduction

Peridot is a gem-quality variety of olivine. It belongs to the forsterite-fayalite mineral series. Peridot is an idiochromatic gem, meaning its colour comes from the basic chemical composition of the mineral itself and not from minor traces of impurities. Thus, peridot is found only in green. In fact, peridot is one of the few gemstones available that can be found only in one color, although the shades of green may vary from light yellowish to dark brownish-green.


The name 'peridot' was derived from the Arabic word for gem - 'faridat'. It is sometimes referred to as 'the poor man's emerald' or as 'chrysolite', a word derived from the Greek word 'goldstone'. It is one of the oldest known gemstones, with records dating back as early as 1500 B.C. Historically, the volcanic island of Zabargad (St. John) in the Red Sea, east of Egypt, had the most important deposit that was exploited for over 3500 years. Today, the finest quality peridot comes from Mogok in Burma, although Pakistani peridot is now highly regarded as well. There are other very important deposits found in Arizona, China and Vietnam. Peridot has also been discovered in fallen meteors and it has also been discovered on Mars and the moon in olivine form.

Chemically, peridot is an iron magnesium silicate and its intensity of color depends on the amount of iron it contains. There may also be traces of nickel and chromium present. Peridot is not especially hard and it has no resistance to acid. On very rare occasions, peridot is known to form with cat's eye chatoyancy (asterism) in the form of four ray stars. Peridot can be mistaken for similar coloured gems, but its strong double refraction is often a very distinguishing trait. In thicker stones, the doubling of lower facet edges can be easily seen by looking down though the table without the need for magnification.

Peridot; Origin and Sources Back to Top

Most gemstones are formed in earth's crust, but peridot is formed much deeper in the mantle region. Peridot crystals form in magma from the upper mantle and are brought to the surface by tectonic or volcanic activity where they are found in extrusive igneous rocks. Historically the volcanic island Zabargad (St. John) in the Red Sea was the location of the most important deposit. It was exploited for 3500 years before it was abandoned for many centuries; later, it was rediscovered around 1900 and has been heavily exploited ever since.

Today, the most important deposits are found in Pakistan (in the Kashmir region and the Pakistan-Afghanistan border region). Beautiful material is also found in upper Myanmar (Burma) and Vietnam. Other deposits are found in Australia (Queensland), Brazil (Minas Gerais), China, Kenya, Mexico, Norway (north of Bergen), South Africa, Sri Lanka, Tanzania and the United States (Arizona and Hawaii). Recently, China has become of the the largest producers of peridot.

Buying Peridot and Determining Peridot Value Back to Top

Peridot Colour

Peridot is one of the few gemstones that comes in a single color. The depth of green depends on its level of iron content. Peridot's color can vary from yellow-green and olive to brownish green and looks best under natural daylight. Its vivid green color does not change under artificial light. The best colored peridot has an iron percentage of less than 15% and typically includes some trace elements of nickel and chromium, which contribute to its colour. A deep and intense green coloured peridot is considered the most desirable and the most valuable.

Peridot Clarity and Luster

Peridot occurs with excellent transparency. Eye-clean specimens are abundant. Larger stones may appear slightly cloudy owing to the presence of inclusions and impurities. When cut and polished, peridot has an attractive, greasy and vitreous luster.

Peridot Cut and Shape

Peridot is typically faceted due to its excellent transparency. Table and step cuts are very popular, as well as unconventional checkerboards. Peridot can be found in many shapes including fancies and traditional rounds, ovals, emeralds (octagons) and cushions.

Peridot Treatment

Peridot is not typically treated or enhanced in any way. However, there have been reports of metal-foiled peridot to increase stability, and some paler stones may be coated with green foil to enhance colour. Imitation peridot can also be found, typically of synthesized spinel or sapphire.

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Peridot

ColoUr: yellowish green, brownish green

Hardness: 6.5 - 7

Refractive index: 1.64 - 1.69

Density: 3.20 - 3.50

Chemical composition: (Mg, Fe)[SiO4]

Crystal structure: orthorhombic

Lustre: vitreous, greasy

Origins: China, Burma, Pakistan, USA, East Africa, South Africa, Brazil, Norway, Egypt.

Prices for peridots (olivine) are highly dependent on the stone's clarity. The best stones have a vivid yellowish-green color.