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cobalt spinel

Spinel is one of the birthstones for August. Among spinels, those that contain a large amount of cobalt and exhibit a bright blue color are called cobalt spinels. The shade of blue is thought to change depending on the cobalt content, and the darker the blue, the more valuable it is.

Karatz GemMagazine
" Cobalt Spinel "

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ナイジェリア産コバルトガーナイト 0.122ctルース

[On sale June 6th, 10 PM JST] Nigerian Cobaltian Gahnite 0.122ct Loose Gemstone with Identification Report Sale price¥18,800
スペイン産コバルトカルサイト 0.289ctルース

[For sale May 18, 10 PM JST] Spanish Cobalt Calcite 0.289ct Loose Stone with Certificate Sale price¥29,800
スペイン産コバルトカルサイト 0.253ctルース

[Sale at 10 PM on May 18th] Spanish Cobalt Calcite 0.253ct Loose Stone with Certificate Sale price¥25,800
ナイジェリア産コバルトガーナイト 0.572ctルース

[On sale May 14 at 10 PM] Nigerian Cobalt-bearing Gahnite 0.572ct Loose Stone with Certificate Sale price¥69,800
Nigerian Cobalt Garnet 0.095ct Loose with Certificate

Nigerian Cobalt Garnet 0.095ct Loose with Certificate Sale price¥18,800
Synthetic Cobalt Spinel 0.831ct Loose Stone with Certificate of Authenticity

Synthetic Cobalt Spinel 0.831ct Loose Stone with Certificate of Authenticity Sale price¥15,800
Congo Cobalt Calcite 1.439ct Loose Stone

Congo Cobalt Calcite 1.439ct Loose Stone Sale price¥18,800
Congo Cobalt Calcite 7.5mm/1.791ct Loose Stone

Congo Cobalt Calcite 7.5mm/1.791ct Loose Stone Sale price¥19,800
ベトナム産コバルトスピネル 2mm/0.031ctルース 日独鑑

Cobalt spinel from Vietnam 2mm/0.031ct loose Japanese-German edition Sale price¥59,800
ナイジェリア産コバルトガーナイト 0.152ctルース 鑑別書

Nigerian Cobalt Garnite 0.152ct Loose Stone with Certificate of Authenticity Sale price¥45,800
コバルトガーナイト 0.216ctルース

Nigerian Cobalt Garnite 0.216ct Loose Stone, Japan-Germany Exchange Sale price¥45,800
ベトナム産コバルトスピネル（カラーチェンジ） 0.082ctルース

Vietnam Cobalt Spinel (Color Change) 2.7mm/0.082ct Loose Stone, Japan-Germany Exchange Sale price¥59,800
タンザニア産コバルトスピネル 0.118ctルース 日独

Tanzanian Cobalt Spinel (Blue Spinel) 0.118ct Loose Stone Japan-Germany Sale price¥29,800
Tanzania Cobalt Spinel 0.211ct Loose Stone JTL Catalog

Tanzania Cobalt Spinel 0.211ct Loose Stone JTL Catalog Sale price¥29,800
スリランカ産コバルトスピネル 0.281ctルース

Sri Lankan cobalt spinel 0.281ct loose stone Sale price¥59,800
Sold out Cobalt Garnite 1 stone (discount available for multiple purchases)

Cobalt Garnite 1 stone (discount available for multiple purchases)

Sold out Limited Edition of 10 Blue Gemstones! 💎 0.142ct Brazilian Paraiba Tourmaline, Euclase from Zimbabwe, 1.17ct Cobalt Spinel (Certificate of Authenticity: Color Shift), Benitoite, and More! Discounts Available for Multiple Purchases!

Limited Edition of 10 Blue Gemstones! 💎 0.142ct Brazilian Paraiba Tourmaline, Euclase from Zimbabwe, 1.17ct Cobalt Spinel (Certificate of Authenticity: Color Shift), Benitoite, and More! Discounts Available for Multiple Purchases!
Sold out Limited to 10 stones: Blue Spinel Gacha, Cobalt Spinel (including color-shifting type), 2 stones with Japanese and German appraisal certificates, and a bonus synthetic cobalt spinel. Discounts available for multiple purchases.

Limited to 10 stones: Blue Spinel Gacha, Cobalt Spinel (including color-shifting type), 2 stones with Japanese and German appraisal certificates, and a bonus synthetic cobalt spinel. Discounts available for multiple purchases.
Sold out Color Change Gacha💎 Burmese Color Change Zircon, Color Shift Sapphire, Color Shift Cobalt Spinel, and More (Multiple Purchase Discounts Available)

Color Change Gacha💎 Burmese Color Change Zircon, Color Shift Sapphire, Color Shift Cobalt Spinel, and More (Multiple Purchase Discounts Available)
Sold out Limited to 2 stones: 1 Nigerian Cobalt Garnite stone (Multiple purchase discounts available)

Limited to 2 stones: 1 Nigerian Cobalt Garnite stone (Multiple purchase discounts available)
Sold out ナイジェリア産コバルトガーナイト 0.346ctルース 鑑別書

[Sales begin 5/6 10 PM JST] Nigerian Cobalt Garnet 0.346ct Loose Stone with Gemstone Identification Report
Sold out Synthetic Cobalt Spinel 0.466ct Loose

Synthetic Cobalt Spinel 0.466ct Loose
Sold out Synthetic Cobalt Spinel 1.342ct Loose Stone with Certificate

Synthetic Cobalt Spinel 1.342ct Loose Stone with Certificate
Sold out Sri Lankan Cobalt Spinel (Blue Spinel) 3.202ct Loose Stone (Needle-like Inclusions) Japan-German Rare Stone

Sri Lankan Cobalt Spinel (Blue Spinel) 3.202ct Loose Stone (Needle-like Inclusions) Japan-German Rare Stone

Sold out 0.278 ct loose Nigerian cobalt gahnite with Japanese and German appraisals

0.278 ct loose Nigerian cobalt gahnite with Japanese and German appraisals
Sold out Synthetic cobalt spinel 1.886ct loose stone

Synthetic cobalt spinel 1.886ct loose stone
Sold out ナイジェリア産コバルトガーナイト 0.299ctルース 鑑別書

Nigerian Cobalt Garnite 0.299ct Loose Stone with Certificate of Authenticity
Sold out イジェリア産コバルトガーナイト 0.171ctルース 鑑別書

Nigerian Cobalt Garnite 0.171ct Loose Stone with Certificate of Authenticity
Sold out タンザニア産コバルトスピネル 0.458ctルース

Tanzanian Cobalt Spinel 0.458ct Loose Stone with Certificate of Authenticity
Sold out Pt950 スリランカ産コバルトスピネル 0.697ct リング

Pt950 Sri Lankan cobalt spinel 0.697ct ring by Nikkei
Sold out ナイジェリア産コバルトガーナイト 0.133ctルース

Nigerian Cobalt Garnite 0.133ct Loose Stone (Color Shift Type) JTL Catalog
Sold out タンザニア産コバルトスピネル 0.284ctルース

Cobalt spinel from Tanzania 0.284ct loose Japanese and German
Sold out ナイジェリア産コバルトガーナイト 0.242ctルース JTL鑑

Nigerian Cobalt Garnite 0.242ct Loose Stone JTL Catalog
Sold out スリランカ産コバルトガーナイト 0.214ctルース JTL鑑

Nigerian Cobalt Garnite 0.214ct Loose Stone JTL Catalog
Sold out スリランカ産コバルトスピネル 0.647ctルース

Cobalt spinel from Sri Lanka 0.647ct loose Japanese German edition
coming soon ナイジェリア産コバルトガーナイト 0.095ctルース

[On sale June 7th at 10 PM] Nigerian Cobalt Hauyne Loose Stone, 0.095ct, with AGL certificate Sale price¥9,800
coming soon ナイジェリア産コバルトガーナイト 0.158ctルース

[On sale June 7th, 10 PM] Nigerian Cobalt-bearing Gahnite, 0.158ct loose stone with gemological report Sale price¥22,800
coming soon ナイジェリア産コバルトガーナイト 0.157ctルース

【On sale June 7, 10 PM JST】Nigerian Cobalt Hauyne 0.157ct Loose with Certificate Sale price¥22,800
coming soon ナイジェリア産コバルトガーナイト 0.154ctルース

[Sale on June 7 at 10 PM] Nigerian Cobaltian Garnet 0.154ct Loose Gemstone with Certificate Sale price¥24,800
coming soon ナイジェリア産コバルトガーナイト 0.123ctルース

[On sale June 7th at 10 PM] Nigerian Cobalt Garnet 0.123ct Loose Stone with Gemstone Identification Report Sale price¥18,800
coming soon スリランカ産コバルトスピネル 0.461ctルース

[Sale on June 7 at 10 PM] Sri Lankan Cobalt Spinel 4.7mm/0.461ct Loose Stone (Japan-Germany certified) Sale price¥69,800
Sold out ベトナム産コバルトスピネル 0.075ct原石（カラーシフト）

Vietnam Cobalt Spinel 0.075ct Rough Stone (Color Shift)
Sold out 非加熱コバルトスピネル（コバルトブルースピネル） 0.740ctルース（シールドカット） GIA

Unheated Cobalt Spinel (Cobalt Blue Spinel) 0.740ct Loose (Shield Cut) GIA
Sold out ナイジェリア産コバルトガーナイト 0.284ctルース

Nigerian Cobalt Garnite 0.284ct Loose Stone JTL Catalog
Sold out ナイジェリア産コバルトガーナイト 0.179ctルース

Nigerian Cobalt Garnite 0.179ct Loose Stone JTL Catalog
Sold out ナイジェリア産コバルトガーナイト 0.707ctルース

Nigerian Cobalt Garnite 0.707ct Loose Stone JTL Catalog
Sold out Nigerian Cobalt Garnite 0.233ct Loose Stone JTL Catalog

Nigerian Cobalt Garnite 0.233ct Loose Stone JTL Catalog
Sold out Nigerian Cobalt Garnite 0.311ct Loose Stone JTL Catalog

Nigerian Cobalt Garnite 0.311ct Loose Stone JTL Catalog

KARATZ Custom Made

Why not take your favorite gemstone that you found at KARATZ and have it made into custom-made jewelry? It will be made by skilled Japanese craftsmen.
We carefully craft each piece of jewelry, starting with the stone setting, to match the individual characteristics of the gemstone.

KARATZ・Five Commitments

So that more people can feel closer to jewellery and enjoy it easily.
We will introduce KARATZ's thoughts on products, the attention to detail and efforts in selecting gemstones and creating jewelry.

KARATZ's Initiatives and Social Contributions

We will introduce KARATZ's efforts, including nurturing the next generation and business collaboration to develop the industry, and supporting children in Sri Lanka, the land of jewels.

KARATZ Books

These are books that KARATZ has been involved in writing, supervising, and planning. They are all books that allow you to enjoy gemstones from various angles. You can also purchase them directly.

jeweler's tools

For those who want to enjoy jewelry more but don't know what tools to use, we will introduce tools that are also used by KARATZ staff. You can also purchase them directly.