THE MINERAL SPINEL

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Spinel is a very attractive and historically important gemstone mineral. Its typical red color, although pinker, rivals the color of ruby. In fact, many rubies of notable fame belonging to crown jewel collections were found to actually be spinels. Perhaps the greatest mistake is the Black Prince's Ruby set in the British Imperial State Crown. Whether these mistakes were accidents or clever substitutions of precious rubies for the less valuable spinels by risk taking jewelers, history is unclear. The misidentification is meaningless in terms of the value of these gems for even spinel carries a considerable amount of worth and these stones are priceless based on their history, let alone their carat weight and pedigree.

Today, expensive rubies are still substituted for by spinel in much the same way a diamond is substituted by cubic zirconia. Not to commit a fraud or theft but to prevent one. Spinel may take the place of a ruby that would have been displayed in public by an owner who is insecure about the rubies safety. The spinel probably is still valuable but better to lose a $100,000 dollar spinel than a $1 million dollar ruby!

Spinel and ruby are chemically similar. Spinel is magnesium aluminum oxide and ruby is aluminum oxide. This is probably why the two are similar in a few properties. Not suprisingly, the red coloring agent in both gems is the same element, chromium. Spinel and Ruby also have similar luster (refractive index), density, and hardness. Although ruby is considerably harder (9) than spinel, spinel's hardness (7.5 - 8) still makes it one of the hardest minerals in nature.

Spinel may be the poorer cousin of ruby, but its pinker color and other qualities make it attractive in its own right. Spinel typically forms nicely proportioned octahedrons. But it is famous for a type of twinning that bears its name, the Spinel Twin Law. Spinel Law twinning is also found in other isometric minerals such as diamond, galena, cristobalite, magnetite, franklinite and other members of the spinel group. This type of twinning produces a twin plane that is parallel to one of the octahedral faces. The plane acts as a mirror plane and produces a left and right side that are mirror images of each other. This may not sound all that spectacular for a very symmetrical mineral like spinel which is loaded with mirror planes. However this mirror plane is not parallel to any of the others and actually lowers the symmetry of the crystal (only in appearances though).

A good description of the twin is hard to explain, but here it goes. The plane falls (of course) in the center of the crystal, dividing it in half. The two octahedron faces parallel to the twin plane are equilateral triangles. Each point of the triangles is doubled across the twin plane with an indentation between them. The crystal looks like it has trigonal symmetry, but the three indentations are a clue that this crystal is a twin. Twins of spinel are rare, but their popularity makes them readily available on the market.

PHYSICAL CHARACTERISTICS:

  • Color is red, green, blue, purple, brown, and black; but red is by far the more common color.
  • Luster is vitreous.
  • Transparency: Crystals are transparent to translucent and sometimes nearly opaque.
  • Crystal System: Isometric; 4/m bar 3 2/m
  • Crystal Habits include the typical octahedron, but can be found as dodecahedrons and combinations of other isometric forms. Also as rounded grains in alluvial placer deposits.
  • Cleavage: None
  • Fracture is conchoidal.
  • Hardness is 7.5-8.0
  • Specific Gravity is 3.6-4.0
  • Streak is white.
  • Other Characteristics: index of refraction is approximately 1.71 - 1.76 and rutile inclusions may produce six or four rayed stars or asterisms.
  • Associated Minerals include calcite, dolomite, corundum and garnets.
  • Notable Occurrences include Burma, Sri Lanka, Brazil and Afghanistan.
  • Best Field Indicators are twinned crystals if present, color, hardness, density and locality.
Spinel Jewelry - Hover over an item for more information
1.20ct t.w. Multi-Stone, Black Spinel Owl Pin Pendant Necklace, Diamonds. 18"
An RS exclusive. Black spinel and diamond accents accompany 1.20 ct. t.w. multi-stones for one colorful owl pin pendant necklace. Includes garnet, tsavorite, iolite and citrine. Wear as a pendant on the included rope chain or alone as a fun brooch pin....Only $135.00 at Ross-Simons
no photo1.20ct t.w. Multi-Stone, Black Spinel Owl Pin Pendant Necklace, Diamonds. 18"
$135.00
Ross-Simons
5mm Black Spinel Inside-Outside Hoop Earrings in Sterling Silver
5mm black spinel rounds provide a sleek contrast on these glossy inside-outside hoop earrings. Includes swirling details on the back. Hinged post, sterling silver earrings.Only $116.25 at Ross-Simons
no photo5mm Black Spinel Inside-Outside Hoop Earrings in Sterling Silver
$116.25
Ross-Simons
Men's Spinel-Inlay Leather Bracelet - KONSTANTINO - Tan
KONSTANTINOMen's Spinel-Inlay Leather BraceletDetailsBlack leather men's Konstantino bracelet.Sterling silver cylindrical station with channel-set black spinels.Silver push-clasp with Konstantino logo.Approx. 3in diam.Handcrafted in Greece.Designer...Only $675.00 at Neiman Marcus
no photoMen's Spinel-Inlay Leather Bracelet - KONSTANTINO - Tan
$675.00
Neiman Marcus
1.73 TCW Oval-Cut Amethyst, Tanzanite and Black Spinal Ring in Platinum over Sterling Silver
. Cast a spell with this stunning amethyst, tanzanite and black spinel scorcher. Spinel is a deep, dark stone that is in the French crown jewels! Set in platinum over sterling silver. Sizes 6-9.Only $85.49 at PalmBeachJewelry
no photo1.73 TCW Oval-Cut Amethyst, Tanzanite and Black Spinal Ring in Platinum over Sterling Silver
$85.49
PalmBeachJewelry
Prehnite and Black Spinel Dome Ring in Sterling Silver
This dome ring centers a cool, minty green prehnite cabochon in a horizontal presentation offset by a blanket of black spinel. Sterling silver ring.Only $95.00 at Ross-Simons
no photoPrehnite and Black Spinel Dome Ring in Sterling Silver
$95.00
Ross-Simons
Dragon-Head Ring - John Hardy - Silver (7)
John HardyDragon-Head RingDetailsNaga means dragon in Balinese and is a symbol of health and prosperity. With intricate dragon detailing, delightfully dark black sapphire, and red spinel accents, who knows what will come your way when you wear this...Only $795.00 at Neiman Marcus
no photoDragon-Head Ring - John Hardy - Silver (7)
$795.00
Neiman Marcus
Dragon-Head Ring - John Hardy - Red (7)
John HardyDragon-Head RingDetailsNaga means dragon in Balinese and is a symbol of health and prosperity. With intricate dragon detailing, smoldering red sapphire, and spinel accents, who knows what will come your way when you wear this John Hardy...Only $795.00 at Neiman Marcus
no photoDragon-Head Ring - John Hardy - Red (7)
$795.00
Neiman Marcus
Beaded Golden Chandelier Earrings - Devon Leigh - Black
Devon LeighBeaded Golden Chandelier EarringsDetails18-karat yellow gold plate with etched finish.14-karat yellow gold French wire backs.Faceted black spinel beads.4 1/4inL x 1 3/4inW.Made in USA.Designer About Devon Leigh:Winner of the Dallas Fashion...Only $370.00 at Neiman Marcus
no photoBeaded Golden Chandelier Earrings - Devon Leigh - Black
$370.00
Neiman Marcus
Labradorite and Black Spinel Six-Strand Necklace With 14kt Yellow Gold
Glittery intertwined beads of labradorite and black spinel form this striking six-strand necklace. Necklace fastens with a 14kt yellow gold fishhook clasp.Only $295.00 at Ross-Simons
no photoLabradorite and Black Spinel Six-Strand Necklace With 14kt Yellow Gold
$295.00
Ross-Simons
Dragon-Head Ring - John Hardy - Red (8)
John HardyDragon-Head RingDetailsNaga means dragon in Balinese and is a symbol of health and prosperity. With intricate dragon detailing, smoldering red sapphire, and spinel accents, who knows what will come your way when you wear this John Hardy...Only $795.00 at Neiman Marcus
no photoDragon-Head Ring - John Hardy - Red (8)
$795.00
Neiman Marcus
4.40ct t.w. Tourmalinated Quartz, Black Spinel Ring Over Sterling
A pear-shaped trendsetter! This 3.20 ct. t.w. black spinel halo brings out the natural variations that thread through the 4.40 ct. t.w. tourmalinated quartz. 14kt yellow gold over sterling silver ring.Only $93.75 at Ross-Simons
no photo4.40ct t.w. Tourmalinated Quartz, Black Spinel Ring Over Sterling
$93.75
Ross-Simons
2.20ct t.w. Multi-Stone, .10ct t.w. Diamond Flamingo Pin Pendant Over Sterling
Clutching a round of rose quartz and spritzed with .10 ct. t.w. diamonds, our flamingo pin pendant flickers with 2.20 ct. tot. gem wt. of white topaz, garnets and pink sapphires. Revolver safety. Fixed bale accommodated 3mm chain. 18kt yellow gold over...Only $495.00 at Ross-Simons
no photo2.20ct t.w. Multi-Stone, .10ct t.w. Diamond Flamingo Pin Pendant Over Sterling
$495.00
Ross-Simons
Black Spinel Multi-Strand Panther Necklace, 3.15ct t.w. Multi-Stones. 17"
Pretty posh and perfectly styled: our black spinel multi-strand necklace with a .25 ct. t.w. emerald-eyed panther center push-button clasp is ready to make a wild fashion statement! Panther is embellished with 2.90 ct. t.w. white and black sapphire....Only $329.95 at Ross-Simons
no photoBlack Spinel Multi-Strand Panther Necklace, 3.15ct t.w. Multi-Stones. 17"
$329.95
Ross-Simons
5.00ct t.w. Black Spinel, .60ct t.w. Diamond Buckle Bangle Bracelet
An RS exclusive. A fun design with glittering contrast. 5.00 ct. t.w. black spinel bangle features an Art Deco-style buckle of .60 ct. t.w. diamonds. Box clasp and hinge, sterling silver bracelet. Diamond birthstones are the perfect gift for April...Only $385.00 at Ross-Simons
no photo5.00ct t.w. Black Spinel, .60ct t.w. Diamond Buckle Bangle Bracelet
$385.00
Ross-Simons
Alexandra Gem Lab-Created Blue Spinel & White Sapphire Ring, Womens
Beat the blues with this large, blue spinel ring, featuring an impressive border of marquise white sapphires. Metal: Rhodium-plated sterling silverStones: Lab-created blue spinel, 25x11mmOther Stones: Lab-created white sapphires, 2-3mm, 6x3mmSetting:...Only $187.49 at jcpenney
no photoAlexandra Gem Lab-Created Blue Spinel & White Sapphire Ring, Womens
$187.49
jcpenney
This Site Awarded
Available SPINEL specimens:
SPINEL specimen SPI-33
$ 77.00 -50% = $ 38.50
Dims: 1.81x0.73x0.53in (4.59x1.84x1.36cm) .... Wt: 0.71oz (20.2g) .... Loc: Kolonna, Sri Lanka
A dozen or more of black spinel crystals are perched on another crystal which I suspect is quartz, but I'm confused by exposed spinel crystals plus a transparent yellow mineral at several broken areas.
no photo
SPI-33
$ 38.50
no photo
see this List of ALL specimens including SOLD ones
 

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