巴林石的礦物學(xué)與寶石學(xué)研究

1、巴林石的礦物學(xué)與寶石學(xué)研究        巴林石是中國四大名石之一，石質(zhì)細(xì)潤、質(zhì)地光潔、色彩絢麗、種類眾多，在國內(nèi)外的知名度越來越高。本文通過現(xiàn)代測試方法對巴林石的礦物學(xué)特征、寶石學(xué)性質(zhì)、巖石化學(xué)特點(diǎn)、礦床成因等進(jìn)行了研究，使巴林石的研究進(jìn)一步系統(tǒng)、科學(xué)、完善。    主要礦物組成的研究表明：巴林石的主要礦物成分為高嶺石族礦物，具體為較有序高嶺石、較有序地開石、高嶺石地開石過渡礦物。通過計(jì)算X射線衍射分析中的結(jié)晶指數(shù)和紅外吸收光譜中的AB值，認(rèn)為從高嶺石高嶺石地開石過渡礦物地

2、開石，結(jié)晶指數(shù)由高低高(即有序度由高低高)，AB值逐漸降低。研究中發(fā)現(xiàn)，當(dāng)?shù)厮追Q的“剛玉”的主要礦物成分為明礬石和石英，硬度較高不適做雕刻石。    魚子凍、水草凍、雞血石是巴林石中的珍貴品種，經(jīng)研究發(fā)現(xiàn)魚子凍中的“魚子”為硬水鋁石，水草凍中的“水草”為赤鐵礦和黑辰砂，雞血石中的“血”為辰砂，巴林石中常見的黑色不透明礦物主要是黃鐵礦。    測定了巴林石的寶石學(xué)基本性質(zhì)，對巴林石進(jìn)行了系統(tǒng)的分類與命名，建議以“類別+題材”的方式對巴林石藝術(shù)品進(jìn)行命名。對巴林雞血石、福黃石、凍石、彩石、圖案石分別進(jìn)行了質(zhì)量評價，提出

3、了評價要素，并進(jìn)行等級劃分。    顏色成因的研究，認(rèn)為白色系列的巴林石，礦物成分為較純凈的高嶺石族礦物，幾乎不含致色元素；紅色系列的巴林石為礦物顆粒間分布的赤鐵礦呈色，若是較淡的粉紅色，則是由于Fe和Mn類質(zhì)同象替代高嶺石中的Al而致色；黃色系列的巴林石，由顆粒間浸染的大量褐鐵礦呈色，F(xiàn)e(3+)進(jìn)入高嶺石礦物的晶格中，由于電子躍遷和電荷轉(zhuǎn)移，也可以產(chǎn)生黃色；黑色系列的巴林石是由于含有黃鐵礦而致色。    運(yùn)用透光率測試、掃描電鏡分析和粒度統(tǒng)計(jì)等測試方法對巴林石透明度的影響因素進(jìn)行了研究，認(rèn)為無色或淺色巴林石，其

4、顆粒度和主要礦物組成是透明度的重要影響因素，如凍石類平均顆粒度小，礦物組成純凈單一，透明度較高。而彩色巴林石，內(nèi)部含有的暗色次要礦物對透明度起主要作用，暗色礦物越多，透明度越差。    區(qū)域巖石化學(xué)分析表明，區(qū)域火山巖為亞堿性系列的鈣堿性巖系，巖石化學(xué)特征表明區(qū)域巖漿活動經(jīng)過了分異結(jié)晶或同化混染作用。巴林石及圍巖的稀土元素特征分析及稀土配分曲線大致相似，表明巴林石的成礦物質(zhì)來源于流紋巖。    測得了巴林石的氫氧同位素組成，認(rèn)為巴林石礦床為熱液蝕變型礦床，估算其成礦溫度約在200230，成礦熱液來源于大氣降水。巴林

5、石的成礦與火山期后熱液作用密切相關(guān)，熱液活動具有多期多階段的特點(diǎn)。強(qiáng)烈的硅化以及明礬石化、高嶺石化、黃鐵礦化是巴林石的重要找礦標(biāo)志，辰砂化和黃鐵礦化是巴林雞血石的找礦標(biāo)志。    在巴林石礦區(qū)東部的白音沙那地區(qū)新發(fā)現(xiàn)了一種艷藍(lán)色、藍(lán)紫色的石料，經(jīng)電子探針，X射線粉晶衍射、紅外吸收光譜等分析，確定其主要礦物組成為藍(lán)線石、石英和葉臘石，新發(fā)現(xiàn)的藍(lán)線石巖屬巴林石的一個新品種。');ReplaceFont('EnDivSummary','Balin Stone is one of the "Chinese Famous

6、Stones " with sleek texture, flowery color and various category, and is well-known at home and aboard. This thesis has done some research on mineralogy, gemology, petrochemistry and deposit genesis of Balin Stones by modern testing methods. So the Balin Stone's study will be more systemic a

7、nd scientific.Study on mineral composition indicates that the main mineral compositions of Balin Stone are ordered kaolinite, ordered dickite and trasitional minerals of kaolinite and dickite. The HL and A/B have been calculated to testify the structural order is higher when mineral compositions are

8、 kaolinite and dickite, but lower when it's kaolinite's and dickite's trasitional minerals. We have discovered the main mineral compositions of some samples which are called "Hard Stone" by indigene are alunite and quartz. It is too hard to be carved.The "roe gel", &q

9、uot;float grass gel" and "chicken-blood stone" is rare and costly. Study on subordinate mineral indicates that the "roe" in "roe gel" is diaspore, the "float grass" in"float grass gel" is hematite and black cinnabar, the "blood" in &qu

10、ot;chicken-blood stone" is cinnabar and the black and opaque mineral in Balin Stone is mainly pyrite.Having mensurated the basal gemological characters, on the basis of which classified and named Balin Stone systematically and suggested to name Balin Stone artworks with "category and subje

11、ct matter". Quality evaluation indicates different evaluation factors with five categories.Colouration mechanism is studied to explain that white Balin Stone is pure kaolinite mineral with little colorgenous elements. Lots of hematites exist in red Balin Stone and work for redness, whereas, the

12、 pink is due to the isomorphous substitution of Fe and Mn. Abundant limonites occurring in intergrain can explain the yellowness, and Fe(3+) can enter into crystal lattice to help for yellowness by electron transition and charge transfer. Black and opaque pyrites in Balin Stone induce blackness.Tran

13、smissivity test, scanning electro-microscopy observation and grain size analysis are adopted to study the influencing factors of transparence. The results show that average grain size and main mineral composition are the influencing factors of transparence to light-colored Balin Stone. The smaller a

14、verage grain size and the purer main mineral composition are, the better transparence is. But to chromatic Balin Stone, dark and opaque subordinate minerals are the main influencing factors of transparence.Analysis of regional petrochemistry shows that regional volcanic rocks belong to the cale-alka

15、-line series of subalkaline series. Characters of petrochemistry indicate regional magma generates fractional crystallization or assimilation and contamination. REE analysis and homoplasy of chondrite-normalized REE patems of Balin Stones and its surrouding rocks indicate that rhyolite is Balin Ston

16、e's source of ore-forming materials.Balin Stone deposit is proved to be hydrothermal ore deposit by testing the hydrogen and oxygen isotopic compositions of Balin Stone. The ore-forming temperature is estimatedto be from 200 to 230 and mineralizing fluid is derived from meteoric water. The miner

17、alization associates with volcanic hydrothermal alteration which has been experiencing a long and complicated process. Silicification, alunitization, kaolinization and pyritization are the important exploration indications to Balin Stone, and cinnabaration and pyritization are the exploration indications to Balin Chicken-blood Stone.The dumortierite rock is cobalt blue and blue-purple, and it's a new discovery at Baiyinshana east to Balin Stone mining area. The mineralogical resear