We have received numerous positive reviews from our customers over the years, below is a selection of some of our favourites.
I've been reading your wonderful book! Thanks for writing it. I wish we could have the same type of book for refractometer, polariscope, microscope. I mean a series of books for each of the main techniques in the world of gemstones!
Carlos Cesari (UK) / August, 2020
I successfully completed the diploma in gemmology. Became the second-highest mark achiever and best student in practicals. Your book helps me a lot with this achievement. Hope to practice the knowledge in the gem field effectively.
Thank you again. With Regards
Prasanna Buddhika Herath (Sri Lanka) /
Colin & Hilary,
Thank You. I received all my items. I finally have a spectroscope that allows me to see the absorption spectra of Gems and a wonderful book that helps explain why I can't see everything. Didn't know that till I read your book. Thanks for the sticker for my book. Love it!
Ken Reder (USA) / July, 2020
Colin & Hilary,
I just realized that the person I am ordering this equipment from is the same person who wrote the book I am reading, A Students Guide To Spectroscopy.. I love your book. It is the best book I've read on this subject. I am learning so much. Thank You!
Ken Reder (USA) / June, 2020
Hello again, Mr. Winter.
I was able to pick up the package from the post office yesterday (Friday, 22nd). I could not pick it up the day earlier due to my current overtime schedule.
The continuation of our gemological studies at the GIA are delayed by the cost but we continue to move forward with independent study. I am not familiar yet with how to use the spectroscope but I have the most important text to help me do so now. My wife and I thank both you and Mrs. Winter for your graciousness in wishing us well and signing our book. It was of particular encouragement to my wife who is hoping we will continue to work harmoniously in our gemological endeavors.
With our great appreciation and respect.
Sean and Mina (USA) / November, 2019
Hi Colin Winter:
I recently ordered a "OPL a students' guide to spectroscopy by Colin H Winter, FGA, DGA." book online. I'd like to let you know that i received the book today. I really appreciate that you send to my address.
I am a recently graduated student from a gemmology certificate program at George Brown College. I found this OPL book was really helpful for my study especially in memorizing many spectrums of gem stones.
Thank you very much, and have a good day.
Caesar Zhang / November, 2019
I have to tell you that this is the best customer service I have ever received in my entire life so thank you so very much. I wish people in the states were as kind as you have been to me. Kindness truly goes a long way.
Thank you so very much again for your kindness.
Pandora (USA) / November, 2019
I received the package today! Time to break out a bottle of your favorite. The instrument is far superior to the one I bought on the internet...the optics provide a clear and bright spectrum that is readable and fairly easy to focus.
Thank you so much for your excellent customer service and support.
Tim (USA) / November, 2019
I will be a honour if Hilary and you will be so kind to sign this book.
In fact this book made by Hilary and you is probably the best guide made for students and I love the teaching approach and the graphic.
I have the 1 edition.
It is straightforward to understand and when I lose my way, I can go back in the book and catch up.
Thanks to both of you for a fantastic tool in the study of spectroscopy for beginners, look forward to the New 2nd edition.
Arnth Kristensen / October, 2019
I received my spectroscope and my stand, I loved them, makes a huge difference with the one I have.
Yamile Said / August, 2019
Just to let you know that I have received the Spectroscope box you sent me. I know you are and FGA and DGA, but you are a real Diamond. A new home for my 35 year old spectroscope and it still looks brand new after countless hours of use. Many thanks again Colin, its been nice to make contact with you again after all these years, you taught me such a lot.
John Pledger (UK) / August, 2019
Hello Colin, I have to tell you that this is the best customer service I have ever received in my entire life so thank you so very much. I wish people in the states were as kind as you have been to me. Kindness truly goes a long way. Thank you so very much again for your kindness. Take care.
Pandora / March, 2018
I received the package today! Time to break out a bottle of your favorite. The instrument is far superior to the one I bought on the internet...the optics provide a clear and bright spectrum that is readable and fairly easy to focus. Thank you so much for your excellent customer service and support.
Tim (USA) / April, 2018
Hello Colin, We received the lamp last Friday and I am brushing up on the equipment through reviewing "A Students Guide To Spectroscopy". Thank you for your assistance and please have a wonderful and Merry Christmas!
Brian L.G. (USA) / November, 2017
Hi Colin, My order arrived yesterday. It looks like a nice piece of kit. Thanks to you and Hillary for signing the book. I shall be getting into it this evening. Best regards.
Colin B. (Canada) / September, 2017
Hi Colin, Just to let you know that the Hylite arrived safely earlier today. I'm really excited about trying it out with the reference set A gemstones at the weekend! Thank you for all your help with my orders. Kind Regards.
Sarah B. (UK) / November, 2017
Hi Mr Winter, We have been advised your book is an excellent resource for students. I am taking the GAA course in Sydney Australia currently. I believe a few of my class may have already ordered from you. So I would very much like to get a few copies for myself. But would also be interested in a bulk lot to distribute to my classmates. Could you let me know cost for 5 copies of OPL01 Students Guide to Spectroscopy please. And of course postage. And maybe quote for 30 copies to be packed and sent. I would very much like mine signed. And maybe one or two others. Thank you.
Murray P. (Australia) / July, 2017
Hi Colin, The books are for myself Alan V. and one of my classmate Pei L. We're both currently second year gemmology students with the GAA and have found the single copy in the lab quite valuable in determining and learning the spectrum of stones and wanted to get our own copies of the book. A few others in the class have managed to find the book locally but we've not had the luck so I thought I’d go to the source! I'm both surprised and glad to hear straight from yourself! I'll leave it to you guys what you write in the dedication :) Thanks once again and i hope you have a safe trip! Regards.
Alan / May, 2017
I have received the two packages for a few days now, and the instruments are all beautifully made, and the book is full of useful tips and very nicely written. I am very happy with them. I am also impressed with the care that goes into the packaging. Many thanks for producing such quality items!
Yvonne L. (Hong Kong) / April, 2017
OPL products carry a well-deserved reputation, and ordering some is basically an investment in itself. By the way, the book (SGT Spectroscopy) is a really handy reference, well-explained.
Ivan / January, 2011
Regarding the spectroscope, the big OPL diffraction grating units are the best, particularly for seeing the 450 nm complex in sapphire (prism units stretch the blue and violet, making it tougher to see weak lines in that region).
Dick Hughes / December, 2010
Your book is absolutely amazing and even better than I imagined! It's an easy read (even for a foreigner who aren't the strongest in languages), it's very descriptive, extremely educational and I love the humour which sneak in here and there. Furthermore Hilary's illustrations are absolutely fantastic! Your little book has quickly become one of my favourites. I couldn't imagine a better guide. A real gem in my collection. It's not often I get a chance to thank an author and an illustrator directly, but here I'm jumping at the opportunity. THANK YOU BOTH, for a marvelous book, for teaching me new exciting things and for making it an easy joy starring at dark bands in a "rainbow" :o)
Hanne / November, 2010
Amazingly I have grown even happier for your book since my last mail. While comparing what I see in my little cheap spectroscope with Hilary's fantastic artwork, I've really come to appreciate the incredible amount of details you've managed to capture. It's a huge help! I've found quite a lot of very very weak lines, especially in light stones, because I knew where to look, and the paper tip are very handy in finding these weak lines as well. The little descriptions are also their weight worth in gold. I have found a single shortcoming, though. I really think this book should come with a severe warning about the addictiveness of spectroscopy.
Hanne / November, 2010
Thank you again excellent customer service... and also fine instruments.
Tapio / November, 2010
Thank you for your prompt service. All looks great, now just have to study up on how to use them... so glad I purchased the book as well.
Andrew / July, 2010
It would be a great honor for me to receive an autographed copy of your book! It appears your work is highly regarded since I checked with those whom I respect and your book was the only one suggested as the best.
Leo / June, 2010
I was so surprised when I got home from work yesterday and Fed Ex came with my package! I was expecting it to take a week or so. Thank you so much for getting it out so quickly. I have spent all morning reading your book and making my first attempts at using the spectroscope. I appreciate all you help.
Christine / March, 2010
All three (packages) arrived in good order thanks to your/someone's excellent packaging skills. They were all so well padded and wrapped obviously by a very experienced packer, and it was very exciting demummifying them to find the instruments intact. So thank you, and especially for having to fiddle around with three separate packages.
Julie / January, 2010
Hi Colin, I have heard these are the BEST spectroscopes out there and I need to build my lab since I'm a distant ed. student at GIA, Carlsbad
Donna / April, 2008
Hello, I would like to buy the opl teaching spectroscope and the 'little' book to accompany it. Highly recommended by the folks on gemologyonline.com.