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$45.00 USD
價格
2097
1

Spinel, 1.71ct, one more time a spectacular result of nature!

存貨單位
尺寸(毫米)
6.800 x 6.700 x 3.600mm
重量 (cts)
1.710
Treatment
No Treatment
Clarity
VS
類型
Faceted
Shape
Cushion
顏色

Spinel ( /spɪˈnɛl/) is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl2O4 in the cubic crystal system. Its name comes from the Latin word "spinella", which means spine in reference to its pointed crystals.

Spinel crystallizes in the isometric system; common crystal forms are octahedra, usually twinned. It has an imperfect octahedral cleavage and a conchoidal fracture. Its hardness is 8, its specific gravity is 3.5–4.1, and it is transparent to opaque with a vitreous to dull luster. It may be colorless, but is usually various shades of pink, rose, red, blue, green, yellow, brown, black, or (uncommon) violet. There is a unique natural white spinel, now lost, that surfaced briefly in what is now Sri Lanka. Some spinels are among the most famous gemstones; among them are the Black Prince's Ruby and the "Timur ruby" in the British Crown Jewels, and the "Côte de Bretagne", formerly from the French Crown jewels. The Samarian Spinel is the largest known spinel in the world, weighing 500 carats (100 g).

The transparent red spinels were called spinel-rubies or balas rubies. In the past, before the arrival of modern science, spinels and rubies were equally known as rubies. After the 18th century the word ruby was only used for the red gem variety of the mineral corundum and the word spinel came to be used. "Balas" is derived from Balascia, the ancient name for Badakhshan, a region in central Asia situated in the upper valley of the Panj River, one of the principal tributaries of the Oxus River. Mines in the Gorno Badakhshan region of Tajikistan constituted for centuries the main source for red and pink spinels.

Spinel is found as a metamorphic mineral, and also as a primary mineral in rare mafic igneous rocks; in these igneous rocks, the magmas are relatively deficient in alkalis relative to aluminium, and aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel. This is why spinel and ruby are often found together. The spinel petrogenesis in mafic magmatic rocks is strongly debated, but certainly results from mafic magma interaction with more evolved magma or rock (e.g. gabbro, troctolite).

Spinel, (Mg,Fe)(Al,Cr)2O4, is common in peridotite in the uppermost Earth's mantle, between approximately 20 km to approximately 120 km, possibly to lower depths depending on the chromium content. At significantly shallower depths, above the Moho, calcic plagioclase is the more stable aluminous mineral in peridotite while garnet is the stable phase deeper in the mantle below the spinel stability region.

Spinel, (Mg,Fe)Al2O4, is a common mineral in the Ca-Al-rich inclusions (CAIs) in some chondritic meteorites.

Spinel has long been found in the gemstone-bearing gravel of Sri Lanka and in limestones of the Badakshan Province in modern-day Afghanistan and Tajikistan; and of Mogok in Myanmar. Over the last decades gem quality spinels are found in the marbles of Lục Yên District (Vietnam), Mahenge and Matombo (Tanzania), Tsavo (Kenya) and in the gravels of Tunduru (Tanzania) and Ilakaka (Madagascar).

Since 2000 in several locations around the world have been discovered spinels with unusual vivid pink or blue color. Such "glowing" spinels are known from Mogok (Myanmar), Mahenge plateau (Tanzania), Lục Yên District (Vietnam) and some more localities. In 2018 bright blue spinels have been reported also in the southern part of Baffin Island (Canada). The pure blue coloration of spinel is caused by small additions of cobalt.



Shipping: For special requests such as express delivery please contact me. For lost stones the seller is not liable, therefore an additional insurance is recommended. Right of return within two weeks after receiving the shipment. Payment via PayPal, Credit Card, or Bank transfer is possible. For the shipping I generally use: Austrian Post or FedEx. Unfortunately from Austria only DHL "express" is possible.

Please pay your stones in between 48 hours or contact me. Otherwise I need to cancel the deal.

If there is anything you shouldn't be satisfied with please just let me now and we will find a way to solve every problem. My aim is to make you happy with beautiful stones of good quality, good communication is the easiest way to find a solution!



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:國家
Registered Shipping 對包含 3 或更多商品的訂單折扣為 $15.00
世界其他地區
Registered Shipping 對包含 3 或更多商品的訂單折扣為 $15.00
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:國家
Standard Shipping - Untracked 對包含 3 或更多商品的訂單折扣為 $15.00
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Standard Shipping - Untracked 對包含 3 或更多商品的訂單折扣為 $13.00

stonehengejpd
stonehengejpd
Selling all kind of gems, great quality at affordable prices, based in the heart of Europe! In case you may have special wishes just let me know :-) If you shouldn´t be satisfied with an order please do not give a negative feedback just let me know and there is always a way to find a solution that everybody is happy!
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已驗證
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  • terryb313
    terryb313
    積極的

    All of the stones I purchased have been amazing ! Unlike others, the pictures and videos are 100% accurate in color and clarity. Seller has integrity and process purchases so seamlessly and quickly. I highly recommend Stonehengejpd!

  • terryb313
    terryb313
    積極的

    I love Stonehengejpd stones ! Purchased many now and if possible , the pictures do not do them justice . Beautiful and Seller is wonderfully attentive . Purchases always arrive much quicker than anticipated . Highly recommended !

  • terryb313
    terryb313
    積極的

    Stonehengejpd does not disappoint. Every gem has been even nicer than the photos show! Very responsive seller who processes transactions smoothly and efficiently. I receive my purchase much sooner than expected.

審計

Gemstone Sheriff計劃允許我們的會員請求對任何產品進行審核,該審核由獨立的 Gemologist 人員完成,該資格人員評估商品描述和圖片的準確性。

送貨細節

船運:
$15.00 :通過 Standard Shipping - Tracked 計算天數
發貨自:
Austria

付款方式

  • paypal
  • stripe
  • escrow
  • gempay
該賣家在 Austria 的交易中添加 20.00% 稅。

概述

列表類型 : Standard
產品編號 : 2090996
開始 : 20th February 2024 12:13 pm PST
* 所有價格均以:貨幣為單位