Detailed sheet

spinel

This is a gem belonging to a group of minerals close to each other and it was many times qualified as liar because it is present in the same deposits of the ruby and sapphire and it has often been confused with these gems.
Some “so-called” rubies are actually spinels, as the Black Prince of the Crown of England or those of the crown of Wittelsbach. It is known since antiquity and origin of its name remains unclear, although it may be an evocation of “small thorns” because of its six-pointed crystals.
The rubicelle focuses on the color orange, yellow or brown.
The broom – spinel is red.
The pleonaste or ceylanite, is of a very dark green and opaque, or even blackish.
The hercynite spinel is a dark green iron spinel of a density of 3.95.
The gahnite or gahno – spinel is red-purple, blue to dark blue, green or black and contains zinc (ZnAl2O4), its density can be up to 4.62.
Picotite is a chromium spinel, it is dark green with a density of 4.2.
The two largest spinels known are at the British Museum, octahedral crystals weighing 520 carats each. Russia has one of 400 carats.



CHEMICAL CHARACTERISTICS

MgAl2O4

aluminum and magnesium oxide



PHYSICAL CHARACTERISTICS

Main color

red

Other colors

blue, colourless, yellow, black, orange, pink, green, purple

all the intensities of colors, from almost colorless to very dark

Color of streak

white

Luster

vitreous

Hardness

8.0 to 0.0

Density

3.54 to 4.62

Cleavage

indistinct

Fracture

conchoidal, uneven



OPTICAL PROPERTIES

Transparency

transparent

some varieties are translucent and opaques

Refractive index

1.712 - 1.760

Double refraction

0.000

zero isotropic. The refractive index of red spinels is around 1.72

visible double refraction

No

Dispersion

0.020(0.011)

Pleochroism

absent

Number of colors

1

Absorption spectrum

685 - 675 - 665 - 595 - 490

for red spinel (chromium spectrum) 632,480,459 for gahnite. 632,585,555,478,458 for the blue (Iron spectrum )

blue spinel spectrum system

violet spinel spectrum system

blue spinel spectrum system

Fluorescence

variable

strong for the red and pink colors, very low for blue

Inclusions

aligned crystals of dolomite and apatite



CRYSTALS PROPERTIES

octahedra, tetrahedra and even more rarely dodecahedrons, often in twinned crystals and flattened.

crystals system

cubic



OTHER INFORMATIONS

Astrological sign

Aquarius, Aries, Cancer, Capricorn, Gemini, Leo, Sagittarius, Scorpio, Taurus

Exploited
sites

They are found where there are rubies and sapphires in the alluvium. In Burma (Mogok region, Namya), Sri Lanka (near Ratnapura), Afghanistan, Tajikistan, Australia, Brazil, United States (New Jersey), Madagascar, Nepal, Nigeria, Tanzania, Thailand.

use in jewelry

In fact it has been widely used in jewelry … but as a ruby, with whom it is very easily confused when it is blood red.
It is therefore quite natural that this gem is increasingly used in jewelry. Spinels are certainly a great opportunity to own a beautiful blood red stone … The “raspberry pink” spinels, recently discovered in Tanzania bring shades of colors in the available palette, rare among the gems. The delicate shades of pink spinels in Tajikistan have no equivalent in the world of jewelry, they go particularly well with the colors of other gems.
Spinel is the stone anniversary of the 22nd year of marriage .

Daily care
and precautions

Solid stone and easy to maintain. Insensitive to household products. It has everything to be used in jewelry, it deserves to be known by its real name! The jeweler must be careful not to heat it too much because it can lose its color intensity.

imitations and
treatments

We know how to synthetize it since 1920.

Historical
healing properties

It would be a very powerful stone, between zircon and garnet, an anchor and realignment stone of the chakras. More powerful than amethyst if it is purple, as much as the schorl if it is black, protecting against negative energies, its properties are similar to those of ruby. The blue spinel would have properties very similar to those of tanzanite.
The powerful red spinels are not recommended for people who are violent, angry and aggressive.
The black spinel is a shield, very powerful, against aggression and negative energies, sending the evil forces, by a mirror effect, back to the darkness from where they originate.

Other
Gems

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