摘一顆天上的流星
Meteorite Fantasy

當流星劃過天際,人們都說立即許願就會夢想成真。如果能夠擁有一顆來自外太空的的流星,豈不是更彌足珍貴?
People say that when you wish upon a falling star, your dreams can come true. Wouldn’t it be even more precious if you owned a meteor from outer space?

text: Michelle Siu

流星落到地球表面就會成為隕石,它們看上去平平無奇,彷彿跟一般石頭無異,只有通過科學家測試其結構和組成物質才能夠辨別。

小行星或彗星的隕石主要分為三個類別,95%為石隕石,主要是岩石;4%為鐵隕石,由鐵與鎳組成;石鐵隕石最罕有,只有1%,即一半岩石,一半金屬。除了來自小行星或彗星,更特別的是地球上還有來自月球和火星的隕石。月球隕石呈淺灰色,主要由斜長岩組成,混合了石和玻璃的碎片,現時全球約有300顆。火星隕石的結晶年齡比小行星小,只有18至20億年,現時全球約有200個火星隕石,為科學家提供重要的火星地殼研究數據。

這些來自外太空的瑰寶,近年紛紛出現在各大拍賣中,有些以原石整塊呈現,有些經過加工成為雕塑藝術品,均受到不少收藏家鍾愛,也許他們都希望能夠藉此吸取天地靈氣吧!隕石收藏自90年代末開始盛行,買賣主要集中在美國,其中美國的圖森市不時都有礦物寶石、化石、隕石展,因此不少收藏家都會去獲取資訊。當時全球隕石收藏家大約200 人,現時已經將近1 萬人。

隕石的價格根據其稀有程度劃分,最貴的月亮隕石一克平均500美元(約4,000港幣),然後是火星隕石,每克200美元(約1,600港幣),其次是石鐵隕石、鐵隕石、石隕石。有一些具科學研究價值的隕石,由於科研單位要收購,也會被賣家抬高價格。雖然地球上共有大約6萬件隕石,但其中的三分之二位於南極洲,永遠不可能出現在大眾的視線範圍。此外,隕石的來源並沒有隨時間增加,每年墜落的數目只有5到6次。隕石的完整性也會大大影響其收藏價值,因科學家必須切開隕石去辨別隕石的種類,所以如今在拍賣市場可見的巨型隕石,其珍罕程度不言而喻,價格比黃金還要高,並且逐年升值。

早前佳士得進行的隕石拍賣中,就有一批令人矚目的拍品,當中包括5萬年前一個墜落在亞利桑那州沙漠並留下一英里闊的凹坑的小行星碎片,估價15 至25 萬美元(約120 至200 萬港幣);以水晶球展現的極罕有石鐵隕石,使人一眼就看到上面閃閃發亮的晶石,不得不感嘆自然界的鬼斧神工,估價1萬至1.5萬美元(約8至12萬港幣);還有切割成方塊並進行表面蝕刻的魏德曼花紋隕石,估價2萬至3萬美元(約16至24萬港幣)。這些由宇宙最強的力量所塑造的藝術品,全部經歷千萬年歷史,讓人不禁驚嘆宇宙的浩瀚無垠和奧妙,而人世間的繁瑣事,就微小得如滄海一粟。

Meteorites look simple, just like usual stones, therefore they can only be distinguished by scientific tests of structure and composition.

There are three main varieties of meteorites. 95% are stony meteorites, 4% are iron meteoritesand the rarest 1% stony-iron meteorites are halfstone, half-metal. Specially, lunar and Martian meteorites are also present on earth. Close to 300 lunar meteorites are currently known and they are made up mainly of light grey anorthosite and of broken rock fragments and glass shards.There are around 200 Martian meteorites worldwide which have relatively young crystallization ages and provide scientists crucial information of the Martian crust.

These treasures from outer space have frequently appeared in major auctions and had a wide popularity among collectors. These precious stones are either unrefined or processed into sculptures. Meteorite collection has become popular since the late 1990s especially in the United States. Collectors liked to go Tucson and visited exhibitions of gems, fossils and meteorites. The numbers of meteorite collectors have now increased from 200 to nearly 10,000.

The prices of meteorites are determined according to their rareness. The most expensive one is lunar meteorite of USD 500 (HKD 4,000) per gram, next is Martian meteorite of USD 200 (HKD 1,600) per gram, followed by stony-iron meteorite, iron meteorite and stony meteorite. Meteorites with scientific research value can have higher prices. Although there are more than 60,000 meteorites on earth, two-thirds of these are from Antarctica and will never be available to the general public. And the resource is barely growing. Each year there are only 5 or 6 fresh falls. Since scientists dissect the meteorites in order to categorize them, it goes without saying that its degree of rarity may cause the value to exceed that of gold and that its value will appreciate in time.

Earlier at Christie̓s meteorite auction there were a number of remarkable auction items including the Canyon Diablo Meteorite associated with the famous asteroid impact that left an almost mile-wide crater in the Arizona desert 50,000 years ago, estimated at USD 150,000-250,000 (HKD 1,200,000 – 2,000,000); specimen perfectly cut into a sphere to show off its crystals and gemstones,
estimated at USD 10,000-15,000 (HKD 80,000 – 120,000); meteorite with a Widmanstätten pattern cut into a cube, estimated at USD 20,000-30,000 (HKD 160,000 – 240,000).