由於綠輝石的化學成分分佈範圍非常廣，雖然前人已歸納出其彈性模量會隨著化學成分而變化，但還不能描述前人研究中所呈現各彈性模量對化學成分的離散情形。因此本研究將以不同綠輝石之化學成分做進一步的探討。
本研究利用鑽石高壓砧及X光進行現地高壓X光粉末繞射實驗，研究兩個不同化學成分樣本（低硬玉輝石及高硬玉輝石）體積隨壓力（P-V）的變化，推算各樣本的彈性模量K值（及其壓力的一階導數K’），並比較二成分綠輝石之彈性模量。
本研究在室溫下收集兩個樣本在實驗壓力範圍（0～23.4 GPa）內的體積-壓力資料，兩個樣本皆未觀察到相變。在本研究中，低硬玉輝石的體彈模量（K值）為116(1) GPa當K’=4或120(2) GPa當K’=3.1(3)；高硬玉輝石的體彈模數為118(2) GPa當K’=4或117(7) GPa當K’=4.3(23)。K值及K’值的重疊代表本研究中兩個樣本的壓縮行為非常相似。本研究兩個樣本與前人研究加以比較可發現，化學成分及結構均會影響綠輝石的K值大小。除高硬玉輝石之外，其他樣本的K與V0的關係可以一個線性關係K= 484.73-0.84V0來描述，而各樣本的Jd含量與K之間可以一線性關係K=114.0+0.3(Jd mol%)來描述。以C2/c空間群的樣本來說，各樣本的分佈可以一個二次方程式K = 113.4 + 0.5822(Jd mol%) - 0.0028(Jd mol%)2描述；P2/n空間群的綠輝石受限於實驗樣品的個數，彈性模量與化學成分間的關係尚未能完整描述。

Due to the wide composition range and the similarity of structures, previous studies suggested that the bulk modulus (K) of omphacite varies with composition. However, this does not fully describe the scattering of the bulk moduli versus chemical composition presented in previous studies. Therefore, omphacite pyroxenes with different chemical composition were used for further investigation in this study.
In the present study, in-situ high pressure powder X-ray diffraction experiments were performed using diamond anvil cell. Two specimens with different chemical composition (one with low jadeite content and the other with high jadeite content) were used to study the bulk modulus (K) and its pressure derivatives (K’).
The P-V data for two omphacite pyroxenes with space group P2/n were collected at room temperature up to 23.4 GPa. No phase transition was observed in these two specimens in the studied pressure range. The bulk modulus of low jadeite content omphacite is 116(1) GPa when K'=4 or 120(2) GPa when K’=3.1(3), and that of high jadeite content omphacite is 118(2) GPa when K'=4 or 117(7) GPa when K’=4.3(23). The values of K and K’ indicate that the compression behavior in both studied pyroxenes is very similar. Compared with previous studies, this study suggests that the change of bulk modulus in different omphacite pyroxenes can be described by considering both chemical composition and crystal structure factors at the same time. Except of high jadeite content sample used in this study, the relation between K and V0 of all the samples can be described with a linear relation K= 484.73-0.84V0. The relation between K and chemical composition (Jd) of all the samples(except high jadeite content sample used in this study) can also be described with a linear relation K=114.0+0.3(Jd mol%). The K-Jd relation for C2/c-structure omphacite is K = 113.4 + 0.5822(Jd mol%) - 0.0028(Jd mol%)2; however, the trend in P2/n-structured omphacite pyroxenes remains unclear due to the numbers of studied specimens.

中文參考文獻
余樹楨，晶體之結構與性質，渤海堂文化事業有限公司，台北，569頁，民國九十二年
黃怡禎，礦物學，地球科學文教基金會，台北，686頁，民國九十一年

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