碳(tan)酸(suan)鹽(yan)礦(kuang)物。成(cheng)分為CaCO3。又(you)稱霰石(shi),與方解(jie)石(shi)等成(cheng)同質多象。斜(xie)方晶(jing)系,晶(jing)體呈(cheng)柱(zhu)狀(zhuang)或矛狀(zhuang),常(chang)(chang)見假六方對稱的三(san)連晶(jing)。集(ji)合體多呈(cheng)皮殼(ke)狀(zhuang)、鮞狀(zhuang)、豆狀(zhuang)、球粒狀(zhuang)等。通常(chang)(chang)呈(cheng)白色、黃白色。玻璃光澤,斷口為油(you)脂光澤。具不(bu)完全的板面(mian)解(jie)理。貝(bei)(bei)殼(ke)狀(zhuang)斷口。莫氏硬度3.5~4.5。比重2.9~3.0。在自然(ran)界文石(shi)不(bu)穩定,常(chang)(chang)轉變(bian)為方解(jie)石(shi)。主要形(xing)成(cheng)于(yu)外生(sheng)(sheng)作用(yong)條件(jian)下,產(chan)于(yu)近代(dai)海底沉(chen)積或粘土中(zhong);石(shi)灰巖(yan)洞穴中(zhong);也(ye)可形(xing)成(cheng)于(yu)內生(sheng)(sheng)作用(yong),產(chan)于(yu)溫泉(quan)沉(chen)積及火山巖(yan)的裂(lie)隙(xi)和氣孔中(zhong),是低溫礦(kuang)物。也(ye)有(you)生(sheng)(sheng)物成(cheng)因(yin)的,產(chan)于(yu)某(mou)些貝(bei)(bei)殼(ke)中(zhong)。
文(wen)石(shi)(shi)(shi)化(hua)學組成(cheng)(cheng)(cheng)為(wei)CaCO3(orthorhombic,正交晶(jing)系(xi)或稱斜方(fang)晶(jing)系(xi))。與(yu)(yu)方(fang)解(jie)石(shi)(shi)(shi)等成(cheng)(cheng)(cheng)同(tong)質(zhi)(zhi)多象。在(zai)文(wen)石(shi)(shi)(shi)的晶(jing)體(ti)結構中,CO32-按近似成(cheng)(cheng)(cheng)六方(fang)最緊(jin)密堆積的方(fang)式排(pai)列,每個(ge)(ge)(ge)Ca2+位于6個(ge)(ge)(ge)CO32-之間(jian),共與(yu)(yu)9個(ge)(ge)(ge)O2-配位,每個(ge)(ge)(ge)O2-則與(yu)(yu)3個(ge)(ge)(ge)Ca2+和一個(ge)(ge)(ge)C4+相(xiang)聯結。晶(jing)體(ti)呈柱狀(zhuang)(zhuang)(zhuang)(zhuang)或矛狀(zhuang)(zhuang)(zhuang)(zhuang),常見假六方(fang)對稱的三連晶(jing),集合體(ti)多呈皮殼(ke)狀(zhuang)(zhuang)(zhuang)(zhuang)、鮞狀(zhuang)(zhuang)(zhuang)(zhuang)、豆狀(zhuang)(zhuang)(zhuang)(zhuang)、球粒(li)狀(zhuang)(zhuang)(zhuang)(zhuang)等。通常呈白色、黃白色。玻璃光澤,斷口(kou)上為(wei)油(you)脂光澤,具不(bu)完全的板(ban)面解(jie)理,斷口(kou)貝殼(ke)狀(zhuang)(zhuang)(zhuang)(zhuang)。摩斯硬(ying)度(du)3.5~4.5,比重2.9~3.0。在(zai)自然(ran)界,文(wen)石(shi)(shi)(shi)不(bu)穩(wen)定,常轉變為(wei)方(fang)解(jie)石(shi)(shi)(shi)。主要形(xing)成(cheng)(cheng)(cheng)于外生作用條(tiao)件下,出現于蛇紋(wen)石(shi)(shi)(shi)化(hua)超基(ji)性巖風化(hua)殼(ke)及石(shi)(shi)(shi)灰巖洞穴中。組成(cheng)(cheng)(cheng)珍珠和軟(ruan)體(ti)動物(wu)貝殼(ke)內壁珍珠層(ceng)的物(wu)質(zhi)(zhi),與(yu)(yu)文(wen)石(shi)(shi)(shi)完全相(xiang)同(tong),但它們是由(you)生物(wu)有機作用所(suo)形(xing)成(cheng)(cheng)(cheng),不(bu)屬于礦(kuang)物(wu)的范疇。
霰(xian)(xian)石(shi)是(shi)碳酸(suan)鹽(yan)礦物。方解(jie)(jie)石(shi)與霰(xian)(xian)石(shi)皆是(shi)自然(ran)發生并常見的兩種(zhong)碳酸(suan)鈣多形(xing)體。霰(xian)(xian)石(shi)的晶格(ge)與方解(jie)(jie)石(shi)的晶格(ge)不同(tong),所以晶體的形(xing)狀(zhuang)(zhuang)也不同(tong)。霰(xian)(xian)石(shi)的形(xing)狀(zhuang)(zhuang)也許是(shi)柱狀(zhuang)(zhuang)晶體或(huo)是(shi)纖維狀(zhuang)(zhuang),偶爾地也有分叉(cha)鐘乳石(shi)狀(zhuang)(zhuang)的,這種(zhong)形(xing)狀(zhuang)(zhuang)叫做鋼花。
化學組成:CaCO3,CaO56.03%,CO243.97%。常含(han)有(you)錳和鐵;
與方解石(shi)化學成分相同(tong),屬同(tong)質多(duo)象(xiang)現象(xiang)。區別在于文石(shi)為正交(jiao)晶(jing)系(xi),方解石(shi)為三方晶(jing)系(xi)。
鑒(jian)定(ding)特征:以其比重(zhong)和(he)方(fang)解(jie)石(shi)(shi)及(ji)白(bai)云(yun)石(shi)(shi)區別;用染(ran)色法與方(fang)解(jie)石(shi)(shi)區別;
成因(yin)產狀:在自然界,文(wen)(wen)石遠少于(yu)方解石。主要(yao)形成于(yu)外生(sheng)(sheng)作用。作為生(sheng)(sheng)物(wu)化學作用的(de)產物(wu),見于(yu)許多動物(wu)的(de)貝殼或骨(gu)骸中(zhong)(zhong)。珍珠的(de)主要(yao)構成物(wu)也是文(wen)(wen)石,海水中(zhong)(zhong)也可(ke)以(yi)直(zhi)接(jie)形成。內生(sheng)(sheng)成因(yin)的(de)文(wen)(wen)石是熱液最后階段的(de)低溫產物(wu),溫泉(quan)沉淀物(wu)中(zhong)(zhong)也有文(wen)(wen)石產出(chu);
斜方(fang)雙(shuang)(shuang)錐(zhui)晶(jing)類,晶(jing)體(ti)常(chang)呈柱(zhu)狀。常(chang)見(jian)單形有(you)斜方(fang)柱(zhu)m、k等,平行雙(shuang)(shuang)面(mian)b、c,斜方(fang)雙(shuang)(shuang)錐(zhui)等。
晶系(xi)和(he)空間(jian)群:正交晶系(xi),Pmcn;
晶(jing)胞參(can)數(shu):a0=4.95Å,b0=7.96Å,c0=5.73Å;
粉(fen)晶數據:3.396(1)1.977(0.65)3.273(0.52)
硬度(du):3.5-4
比重:2.94g/cm3解理(li):解理(li)不(bu)完全(quan)
斷口:貝殼(ke)狀斷口
顏色:無(wu)色或白色
條痕:無色
透明度:透明
光澤(ze):玻璃光澤(ze),斷口油脂光澤(ze)
發光性:無
薄片中無(wu)色。二軸晶(-)。Np=1.5961,Nm=1.6174,Ng=1.6218。
文石(shi)(shi)由霰(xian)石(shi)(shi)、方解石(shi)(shi)、鐵氧化物(wu)(wu)、蛋(dan)白石(shi)(shi)等礦物(wu)(wu)所組成,屬次生(sheng)礦物(wu)(wu),其(qi)中以霰(xian)石(shi)(shi)為主要成分,呈葡萄(tao)狀或(huo)球(qiu)狀集合體,硬度(du)為3~4,比重(zhong)3.0,良質文石(shi)(shi)顏色較深,硬度(du)高,花紋(wen)多(duo)變化,具有同心圓構造。黃色、乳白色、無花紋(wen)屬中級文石(shi)(shi)。
文石賦存于多孔(kong)(kong)質玄(xuan)武巖(yan)的(de)氣孔(kong)(kong)和裂隙內,生(sheng)成過程似在氣孔(kong)(kong)的(de)圍巖(yan)壁上先生(sheng)成一層綠(lv)泥石或(huo)(huo)褐鐵礦薄(bo)膜,文石眼生(sheng)于其(qi)上,最后再填充霰石或(huo)(huo)方解石于其(qi)空隙中(zhong)。
塊狀構造(zao),各(ge)種礦物成(cheng)(cheng)不規則混合(he)。縞狀構造(zao),以(yi)霰石及玉髓等數種不同礦物,形成(cheng)(cheng)明顯之同心(xin)縞狀充填其中(zhong)。
品(pin)質較佳者,經加工打磨后(hou)呈現美麗的同(tong)心圓花紋,稱為文(wen)石眼(yan),可(ke)制成(cheng)文(wen)石飾物制品(pin)、印材等。
中國西藏臺灣及意(yi)大(da)(da)利西西里(li)島,西藏的文石(shi)礦(kuang)發現世界(jie)最(zui)深(shen)最(zui)長大(da)(da)雅魯藏布(bu)大(da)(da)峽(xia)谷人跡罕至(zhi)地帶,臺灣澎湖文石(shi)主要分布(bu)于望(wang)安島,將軍澳,西嶼(yu),七美(mei)等嶼(yu)沿岸。以雅魯藏布(bu)大(da)(da)峽(xia)谷的礦(kuang)料(liao)最(zui)具寶石(shi)價值(zhi)。
澎湖(hu)列島(dao)山(shan)美,水美,石(shi)(shi)更美,澎湖(hu)文(wen)石(shi)(shi)馳名海內外,是(shi)收(shou)藏(zang)家爭相(xiang)收(shou)藏(zang)的奇石(shi)(shi)。文(wen)石(shi)(shi)稀(xi)少珍貴(gui)。世界上(shang),只有(you)我國臺灣(wan)省(sheng)的澎湖(hu)群島(dao)和(he)意大利的西西里島(dao)出(chu)產(chan)文(wen)石(shi)(shi)。澎湖(hu)的文(wen)石(shi)(shi)又因色彩鮮(xian)艷(yan),質地優良,有(you)天然的“貓眼”,而備(bei)受青睞。澎湖(hu)列島(dao)是(shi)火山(shan)爆發形(xing)成的玄武巖島(dao)。文(wen)石(shi)(shi)生(sheng)成于(yu)玄武巖杏仁狀空隙和(he)裂縫里,主要成分是(shi)霰(xian)石(shi)(shi)、石(shi)(shi)英類和(he)氧化(hua)鐵,屬于(yu)次生(sheng)礦(kuang)石(shi)(shi)。
澎(peng)湖(hu)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)主(zhu)要產于望(wang)安(an)島(dao)、將(jiang)軍(jun)嶼(yu)、白沙島(dao)以及(ji)風柜半(ban)島(dao)。望(wang)安(an)島(dao)是(shi)(shi)澎(peng)湖(hu)列島(dao)中(zhong)的(de)第四大(da)島(dao),也是(shi)(shi)最(zui)早開采(cai)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)的(de)地方。這里的(de)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi),色澤深,硬度(du)高,質(zhi)(zhi)地優,但由于過量開采(cai),資源已(yi)枯(ku)竭;將(jiang)軍(jun)嶼(yu)出產的(de)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi),色彩艷麗(li),質(zhi)(zhi)地堅硬,以文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)眼(yan)和(he)鑲(xiang)金(jin)邊文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)最(zui)名貴;白沙島(dao)出產的(de)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi),以淡(dan)黃、綠色或乳白色為主(zhu),色彩淡(dan)雅,造型別致,其(qi)(qi)中(zhong)同心花(hua)紋(wen)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)、葡(pu)萄狀文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)最(zui)珍貴;風柜半(ban)島(dao)出產的(de)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)色澤華麗(li),質(zhi)(zhi)地細膩,上面常帶有(you)天然的(de)精(jing)美圖案,其(qi)(qi)中(zhong)的(de)千眼(yan)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)更(geng)是(shi)(shi)稀少,一年(nian)出產不過幾十枚,非(fei)常珍貴。澎(peng)湖(hu)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)經過打磨加工(gong)成(cheng)印章、戒指、項鏈、領帶夾等各種工(gong)藝品和(he)飾物,人見人愛(ai)。臺(tai)灣不少雕刻(ke)家(jia)嘗試用文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)雕刻(ke)精(jing)巧的(de)器具,使(shi)文(wen)(wen)(wen)(wen)(wen)石(shi)(shi)(shi)的(de)名聲(sheng)更(geng)加遠揚(yang)。
文(wen)石(shi)(shi)名貴稀少,價值不菲(fei),雕刻前,藝術家(jia)往往要反(fan)復構思,巧妙利用原材料的(de)(de)(de)(de)色彩和(he)特點,塑(su)造出完美(mei)的(de)(de)(de)(de)作品(pin)。文(wen)石(shi)(shi)作品(pin)取(qu)材廣泛,造型千變萬(wan)化(hua),有(you)的(de)(de)(de)(de)出自歷(li)史(shi)和(he)民間故(gu)事,有(you)的(de)(de)(de)(de)選(xuan)自神話(hua)傳說,更多(duo)的(de)(de)(de)(de)則是佛(fo)像、鳥獸(shou)魚蟲和(he)文(wen)房四(si)寶,件件作品(pin)都栩栩如(ru)生。臺灣澎湖文(wen)石(shi)(shi)是中(zhong)國傳統賞(shang)石(shi)(shi)文(wen)化(hua)中(zhong)的(de)(de)(de)(de)一朵奇葩(pa),它從古老的(de)(de)(de)(de)歲月中(zhong)走(zou)來,藝術家(jia)又賦予了它新的(de)(de)(de)(de)生命。