How is Citrine Formed?

The yellow variety of quartz is called citrine. It may be natural, but in Brazil the natural citrine is very rare. What is done is to “burn” the amethysts. Eight hours to 400 degrees Celsius and it’s done. However there is more to it. It’ll depend on the amethyst. Not all amethyst turns yellow or into citrine. During the heat treatment, some amethyst will crack, others do not change colour, others become milky and such. There are so many tricks in the process and the amethyst need to be from the right mine.

//:Amethyst Barbecue (—/image/—)

But who, after all, has discovered that burnt amethyst turns yellow? A German immigrant, August Lamberts, worked with amethyst in Rio Grande do Sul. In 1883 he used some “weak”, pale or low value amethyst geodes to make a barbecue like the one I photographed near Ametista do Sul (RS) few years ago (see below). He roasted a barbecue for dinner, and in the morning discovered that the amethyst geodes were coloured with tints from yellow to red. Thus the Brazilian (Rio Grande) citrine industry was born.

-- Translated from original Portuguese text: Prof. Heinrich Theodor Frank’s post:…


15 Days of Giveaways! - Stonebridge Imports is turning 15!

October 19, 2017

In celebration of our 15th anniversary we have decided to say THANK YOU, THANK YOU, THANK YOU! to all of our wonderful customers by giving away a different item for each year open. Each day an item will be posted, where all you have to do to enter to win is either like and share the [...]

Geo Mine Tour: "Wonders of the South" Tour. Adventures for the gem & mineral lover, student, professional or dealer. Fun, educational and professional. Discover, explore and shop.

June 19, 2017

"Wonders of the South" will take you to a breathless location in the far South of Brazil, the State of Rio Grande Do Sul. Massive mountains of basalt store Amethyst and Citrine geodes in its interior. Other treasures you will see are agates, amethyst flower, selenites and calcites. Geo Tour will take you to see [...]


1st. Buying Trip To Mexico: New Amazing Crystals Coming...!

August 20, 2016

We've been buying Mexican products for many years, but this is actually the first time to visit a manufacturer in East-Central Mexico. I was very impressed with the manufacturer's organization and plant size, in fact, one of the biggest on this industry I've seen lately. In their more than 50,000 sq.ft. manufacturing plant, show room [...]


Directions to Stonebridge's Extra New Warehouse

March 4, 2018

Look inside for a Google map driving directions and scroll down for location access pictures.