Gemological properties of 20 faceted amethysts supplied by the Geostone Group were analyzed using standard gem testing instruments. The samples were representative of the material produced from this locality in both their color (light pinkish purple to dark reddish purple) and size range (6.06–17.92 ct).
Refractive indices and birefringence values were obtained with a standard refractometer and a near-monochromatic light source. Specific gravity was determined using a Mettler-Toledo hydrostatic meter. Reactions to ultraviolet radiation were observed using standard long-wave (365 nm) and short-wave (254 nm) lamps. Visible absorption spectra were obtained with a Krüss prism spectroscope. Visual features were observed using an SZM-2 zoom microscope from Gemmarum Lapidator with darkfield illumination at 20×–80× magnification. Inclusions were photographed with an Olympus BX41 microscope using immersion techniques.
Chemical composition data were obtained with semi-quantitative, non-destructive EDS microanalysis for determination of major and minor elements. Micro-Raman spectroscopy was used for mineral inclusion identification purposes.
EDS data were acquired at Turin University’s Department of Earth Science using a Cambridge Stereoscan 360 scanning electron microscope, equipped with an Oxford Inca Energy 200 EDS for microanalysis and a Pentafet detector and an ultrathin window for the determination of elements with atomic number down to boron. All spectra were obtained at 15 kV accelerating voltage, 25 mm working distance, and 1 µA probe current for 60 to 300 seconds. Primary standardization was performed on SPI Supplies and Polaron Equipment analytical standards. Daily standardization was performed on a high-purity metallic cobalt standard.
Unoriented micro-Raman spectra were obtained at Turin University with a HoribaJobin Yvon LabRam HRVIS apparatus, equipped with a motorized x-y stage and an Olympus microscope. The backscattered Raman signal was collected with a 50× objective, and the Raman spectrum was obtained for a non-oriented position. The 632.8 nm line of a He-Ne laser was used as the excitation wavelength; laser power was controlled by a series of density filters. The minimum lateral and depth resolution was set to a few µm. The system was calibrated using the 520.6 cm–1 Raman band of silicon before each experimental session. The spectra were collected in 8 to 10 acquisitions with single counting times ranging between 40 and 120 seconds. Spectral manipulation such as baseline adjustment, smoothing, and normalization were performed using the LabSpec 5 software package (HoribaJobin Yvon, 2004 and 2005). For band component analysis, we used the Fityk software package (Wojdyr, 2010), which enabled us to select the type of fitting function and fix or vary specific parameters accordingly. The spectra were recorded for the 100–1300 cm–1 range using the LabSpec 5 program.
คุณสมบัติ gemological ของพลอยสีม่วงประกอบที่ 20 ที่จัดทำ โดย กลุ่ม Geostone ได้วิเคราะห์โดยใช้อัญมณีมาตรฐานการทดสอบเครื่องมือ ตัวอย่างดีตัวแทนของวัสดุที่ผลิตจากท้องถิ่นนี้ในทั้งสี (แสงสีบัวโรยเพื่อดำน้ำตาลสีม่วง) และช่วงขนาด (6.06 – 17.92 ct) Refractive ดัชนีและค่า birefringence ได้รับ refractometer มาตรฐานและแสงใกล้ยัง แรงโน้มถ่วงเฉพาะที่ถูกกำหนดโดยใช้เครื่องวัดทดสอบที่หยุดนิ่งของ Mettler Toledo ปฏิกิริยากับรังสีอัลตราไวโอเลตสุภัคใช้คลื่นยาวมาตรฐาน (365 nm) และ คลื่นสั้น (254 nm) โคมไฟ แรมสเป็คตราดูดซึมปรากฏได้รับกับเป็น spectroscope ปริซึม Krüss คุณลักษณะภาพได้สังเกตด้วยกล้องจุลทรรศน์การซูม SZM 2 จาก Gemmarum Lapidator รัศมี darkfield ที่ 20 ×× – 80 ขยาย ตัวที่ถ่าย ด้วยกล้องจุลทรรศน์โอลิมปัส BX41 การใช้เทคนิคการแช่ ข้อมูลองค์ประกอบทางเคมีได้รับกับ microanalysis EDS กึ่งเชิงปริมาณ แบบไม่ทำลายสำหรับการกำหนดองค์ประกอบหลัก และรอง กไมโครรามันถูกใช้สำหรับรหัสการรวมแร่ EDS data were acquired at Turin University’s Department of Earth Science using a Cambridge Stereoscan 360 scanning electron microscope, equipped with an Oxford Inca Energy 200 EDS for microanalysis and a Pentafet detector and an ultrathin window for the determination of elements with atomic number down to boron. All spectra were obtained at 15 kV accelerating voltage, 25 mm working distance, and 1 µA probe current for 60 to 300 seconds. Primary standardization was performed on SPI Supplies and Polaron Equipment analytical standards. Daily standardization was performed on a high-purity metallic cobalt standard. Unoriented micro-Raman spectra were obtained at Turin University with a HoribaJobin Yvon LabRam HRVIS apparatus, equipped with a motorized x-y stage and an Olympus microscope. The backscattered Raman signal was collected with a 50× objective, and the Raman spectrum was obtained for a non-oriented position. The 632.8 nm line of a He-Ne laser was used as the excitation wavelength; laser power was controlled by a series of density filters. The minimum lateral and depth resolution was set to a few µm. The system was calibrated using the 520.6 cm–1 Raman band of silicon before each experimental session. The spectra were collected in 8 to 10 acquisitions with single counting times ranging between 40 and 120 seconds. Spectral manipulation such as baseline adjustment, smoothing, and normalization were performed using the LabSpec 5 software package (HoribaJobin Yvon, 2004 and 2005). For band component analysis, we used the Fityk software package (Wojdyr, 2010), which enabled us to select the type of fitting function and fix or vary specific parameters accordingly. The spectra were recorded for the 100–1300 cm–1 range using the LabSpec 5 program.
การแปล กรุณารอสักครู่..
