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【GIA 2023 冬季】绿柱石的微观世界 上

 宝石学读书会 2024-03-16 发布于陕西

写在前面:方便同学们学习,今天开始发布的文章均为中英文对照,希望对大家有所帮助。

The beryl group of beryllium silicate minerals currently contains six member species, all of which have a hexagonal crystal structure: beryl, pezzottaite, bazzite, avdeevite, stoppaniite, and the most recent member, johnkoivulaite, which was named as a new mineral in 2019 after GIA’s analytical microscopist, John Koivula. As faceted gems, beryl and pezzottaite are the most commonly encountered species. Beryl is the most common beryllium-containing mineral and often forms in pegmatitic environments or as a product of metasomatism. Also possible is a unique set of conditions in which beryl can crystallize from magma-derived gases and groundwater, as in the case of the red beryl deposit in the state of Utah. Beryl gems include blue aquamarine), golden beryl, red beryl, pink morganite, colorless goshenite, as well as Maxixe beryl, which is commonly dark blue with an unstable color. Emerald is the green variety of beryl colored by chromium and/or vanadium. Pezzottaite was first discovered in a granitic pegmatite in Madagascar in 2002 . This unique bright pink beryl mineral has high cesium and lithium contents, which differentiate it as a unique beryl-group mineral.

Be硅酸盐绿柱石族矿物含有六个矿物种,均具有六方晶系晶体结构,分别为绿柱石、pezzottaite铯柱石(化学式为Cs(Be2Li)Al2Si6O18)、bazzite钪柱石(化学式为Be3(Sc,Al)2Si6O18)、avdeevite(以Na为主的碱性绿柱石)、stoppaniite[化学式为(Fe,Al,Mg)4(Be6Si12O36)*(H2O)2(Na,□),发现于意大利],以及2019年最近发现的新成员johnkoivulaite[化学式为Cs(Be2B)Mg2Si6O18,发现于缅甸抹谷宝石矿区]。作为一种刻面型宝石,绿柱石族矿物中绿柱石和铯柱石最为常见,其中绿柱石是最常见的含铍矿物,通常形成于伟晶环境,或作为一种交代作用的产物,也可作为一种地质构造的特征矿物,在这种环境下,绿柱石结晶于岩浆成因的气体和地下水中,例如犹他州的红色绿柱石矿床。绿柱石宝石包括蓝色的海蓝宝石、金绿柱石、红色绿柱石、粉色摩根石、无色绿柱石、深蓝色的马希谢绿柱石(颜色不稳定)、绿色的祖母绿(由Cr或V致色)。2002年,在马达加斯加首次发现铯柱石(Pezzottaite),呈现特有的亮粉色,具有高Cs、高Li的特征,使得它成为绿柱石矿物族中的独立矿物。

Many of the beryl examples in the accompanying wall chart crystallized from a pegmatitic environment in which there is a high enough beryllium concentration for these gems to crystallize, which require the element as it is a bulk part of the crystal structure. These pegmatitic environments often contain fluids that get trapped along with other pegmatitic minerals, leaving a signature of their geologic formation within the gem’s interior. The minerals most likely to be observed in these pegmatitic gems include albite, apatite, muscovite, garnet, tourmaline, and quartz (Gübelin and Koivula, 1986), while rare minerals such as stibiotantalite and monazite are only occasionally encountered.

集中很多绿柱石的例子均形成于伟晶环境,由于Be是组成晶体结构的主要组成,而这种环境中具有足够高的Be,足以使这类宝石发生结晶。伟晶环境中通常含有流体,可被其他伟晶矿物捕获,形成保留地质信息的内部特征。在这些伟晶矿物中最常见到的矿物包裹体包括钠长石、磷灰石、白云母、石榴石、电气石和石英,但是,偶尔可见一些稀有矿物,如钽锑矿、独居石等。

This chart will focus on the members of the beryl group commonly seen as gems but will exclude emerald, which already has its own inclusions chart. While synthetic and treated beryl gems do exist, they are relatively uncommon, so this chart only deals with natural beryl. These include fluids and solid minerals, as well as surface features and structural inclusions. As with past charts, the images presented are not meant to be all-encompassing but offer a wide range of the possible types of inclusions found in beryl gems.

本图集中专注视作宝石的绿柱石族成员,但不包括祖母绿(已有自己独立的图集),虽然合成和优化处理绿柱石确实存在,但相对不常见。因此本图集仅涉及天然绿柱石族矿物。包括流体包裹体、固相矿物包裹体以及表面特征和结构特征等。与过去的图集相同,所呈现的图集并不意味着涵盖所有,但提供了绿柱石族宝石中广泛发现的可能存在的内含物类型。

This 9.885 kg specimen of aquamarine on albite with a quartz cathedral center, measuring 31 × 23 × 28 cm, is from Pakistan’s Shigar Valley. Courtesy of GIA Museum, collection no. 43068. Photo by Robert Weldon.

样品重9.885公斤,尺寸为31 × 23 × 28 cm,产自巴基斯坦Shigar谷,海蓝宝石与石英和钠长石共生。收藏于GIA博物馆,编号43068。摄影:Robert Weldon

This aquamarine has been significantly etched, resulting in a cave-like cavity filled with sharp spires of beryl. Field of view 3.28 mm.
这颗海蓝宝石经历过明显的溶蚀作用,使其内部形成了一个空穴,内部充填了绿柱石的锥状物。视域3.28mm
A complex fluid inclusion and etch ribbons are present in this morganite from Minas Gerais, Brazil. Field of view 2.78 mm.
产自巴西米纳斯吉拉斯州摩根石,其中可见复杂的立体包裹体和蚀刻带状物。视域2.78mm
Hexagonal growth zoning in this aquamarine from Brazil is revealed using polarized light. Field of view 15.67 mm.
产自巴西的海蓝宝石,正交偏光镜下可见明显的六边形色带。视域15.67mm
A rare inclusion of beryl is preserved in this fluorite crystal from Inyo, California. Field of view 8.6 mm.
萤石晶体中罕见的绿柱石包裹体,样品产自加利福尼亚Inyo矿区,视域8.6mm。
Skeletal dendritic inclusions of ilmenite are the cause of silvery aventurescence in this aquamarine from Brazil. Field of view 2.59 mm.
海蓝宝石中树枝状钛铁矿包裹体,是其产生砂金效应的原因。视域2.59mm
This morganite crystal shows a heart-shaped etch feature on the pinacoid face, as seen using differential interference contrast microscopy. Field of view 1.5 mm.
利用微分干涉差显微镜观察,可见摩根石晶体中具有一个心形的蚀刻特征。视域1.5mm。
A goshenite beryl from Pakistan is host to pinkish orange crystals of the rare mineral zwieselite. Field of view 7.61 mm.
产自巴基斯坦的无色绿柱石,其中可见粉橙色晶体,为罕见的氟磷铁石(zwieselite)
Galenobismutite was identified in the rare beryl-group mineral pezzottaite. Field of view 0.91 mm.
铯柱石中的辉铅铋矿。视域0.91mm
Transparent green crystals of monazite along with black ferrocolumbite crystals are seen in this goshenite from Pakistan. Field of view 4.49 mm.
产自巴基斯坦的无色绿柱石,内部可见透明的绿色独居石 晶体,伴生黑色铌铁矿。视域4.49mm。

This complex fluid inclusion in beryl, which resembles an eagle’s head, contains a liquid, gas, and numerous solid crystals that show birefringence using polarized light. Field of view 3.55 mm.
绿柱石中复杂的流体包裹体,其形态类似于鹰头,正交偏光镜下观察可见内部气相、液相和多个固相晶体包裹体。

A fluid-filled, three-phase inclusion in beryl showing thin-film interference under oblique fiber-optic lighting. Field of view 3.52 mm.
使用斜向光纤照明法,叫可见绿柱石中充满液体的三相包裹体所形成的薄膜干涉。视域3.52mm
This aquamarine from Brazil contains planes of numerous fluid inclusions that show a “bubble in bubble” effect resulting from the immiscibility of an aqueous liquid and carbon dioxide liquid and gas phases. Field of view 1.79 mm.
产自巴西的海蓝宝石,可见大量的流体包裹体,其内部为不混溶的液态水、液态二氧化碳和气相二氧化碳,呈现出“气泡中的气泡”的效果。视域1.79mm
A euhedral crystal of kunzite is preserved in this morganite from Minas Gerais, Brazil. Field of view 8.81 mm.
产自巴西米纳斯吉拉斯州的摩根石,其内部可见自形的紫锂辉石。视域8.81mm
Small blue crystals of gahnite are observed in this cat’s-eye heliodor reportedly from Brazil. Field of view 1.10 mm.
样品为产自巴西的金绿柱石猫眼,可见小的蓝色锌尖晶石晶体。视域1.10mm

Etch features containing yellow epigenetic limonite are present in this rare example of johnkoivulaite, recognized as a beryl-group mineral in 2019. Field of view 1.88 mm.
罕见的johnkoivulaite,2019年被认为属于绿柱石族。其内部可见含有黄色的后生褐铁矿包裹体的蚀刻特征。视域1.88mm。

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