The Gemstones


Max Ostro was always driven by a passion for color. He spent years exploring exotic regions of the earth in his quest for gems of rare beauty.

It was Blue Topaz, a then relatively unknown gemstone, that held him in its thrall. Fascinated by the vibrancy of this stone, Max worked tirelessly to advance our understanding of topaz and especially the cuts and shapes which would best reveal its inner beauty.

Thanks to his many years of dedication, topaz is now one of the most highly coveted gemstones in the world. Max’s legacy is a range of the finest blue topaz gemstones: ostro topaz, which is presented here in honor of his memory.



Story of Topaz

Topaz gemstones can be discovered in a multitude of different colors and hues, but those that do possess a natural color are rare.

The etymology of “topaz” derives from the ancient Sanskrit word for fire, due to the great heat that these gemstones are subjected to in the process of their geological formation. No less historic is the stone’s allure, which dates back thousands of years, with various cultures ascribing to it powers of healing, strength, and protection. This enduring fascination is a testament to its stunning beauty.

World Famous Topaz Gemstones

World Famous
Topaz Gemstones

  • The Ostro Stone

    This vividly blue, oval-cut topaz weighs 9,391 carats. Mined in Brazil over 20 years ago, it is the world’s largest known topaz of this intense color.

  • Topaz Azul

    The Topaz Azul is a beautiful, flawless, vivid blue cushion-cut topaz weighing 8,225 carats. Mined in Minas Gerais, Brazil, it is now part of the Programa Royal Collections in Spain.

  • Brazilian Princess Topaz

    Once the largest faceted gemstone in the world at 21,005 carats, this light blue, emerald-cut gemstone, is in the collection of the American Museum of Natural History in New York.

  • Braganza Diamond

    This legendary colorless gemstone, belonged to the Portuguese Royal House of Braganza and disappeared without a trace after the death of King John VI in 1826. It weighed 1,640 carats and was originally thought to be a diamond.

  • El-Dorado Topaz

    The “El-Dorado Topaz” is the largest faceted gemstone in the world, weighing 31,000 carats. The stone is emerald-cut, with good clarity and a yellowish-brown color. It is now part of the Programa Royal Collections.

Learn About Gemology

Gemology of Topaz

Topaz is a hard, brilliant, transparent stone. The silicate mineral, composed of aluminum and fluorine, crystallizes in vapor pockets during lava flows. This occurs in cavities within granite or rhyolite igneous rock, pegmatite dikes, high temperature quartz veins and alluvial deposits. Topaz is found primarily in Brazil, Nigeria, Ceylon (Sri Lanka), Mexico, China, Russia and the United States. Topaz hardness is 8 on Moh’s scale indicating that its resilience to scratching is superseded only by diamond and corundum.


Topaz is a silicate mineral (specifically Aluminum fluorohydroxysilicate)

Chemical formula:

Al2 SiO4(F,OH) 2



Crystal structure:




GIA clarity type:

1 – refers to transparent stones that often appear in nature with no visible inclusions. They have icy clarity and even the smallest inclusion may be cause to reject for use in jewelry.

Moh’s Scale:

Topaz is classified as an 8 on The Moh’s Scale of mineral hardness, one of the hardest materials on earth.

Mohs Scale

About Ostro

Beauty without compromise

Max Ostro was a pioneer in the development of blue topaz and instrumental in its popularity today. Even the terms “London blue” and “Swiss blue”, commonly used to describe the various shades of blue topaz, have long been associated with the Ostro family.


Cutting Topaz

ostro topaz are masterfully cut to maximize their intensely blue color, their brilliance and pristine lustre.

While rough and dull in its raw state, topaz is amongst the world’s hardest stones, making it ideally suited for a dazzling cut and a lustrous polish. Rough topaz material is first studied for its suitability, with selected stones then being marked for specific cuts based on their natural shape and color potential. The selected stones are then formed and faceted, followed finally by a series of sanding, smoothing, and polishing procedures to produce a brilliant lustre.

Bringing Out the Beauty



Since the discovery of gemstones, mankind has used techniques to unlock their latent beauty, from the “oiling” of emeralds to the “burning” of rubies and sapphires.

These processes have been progressively advancing over millennia and Ostro Minerals has worked for decades with leading gem experts to harness the most sophisticated techniques. ostro topaz represents the pinnacle of these achievements resulting in magnificent shades of blue. Our company is a leader in the development of the highest regulatory standards and was the first business in the blue topaz industry to be licensed by the US regulatory authorities.

Company History

A legacy of brilliance™

max astro

Max Ostro, the man responsible for this legacy, began his journey through the gemstone industry in the 1960s. Initially representing Mexico for its renowned opals in international exhibitions, he later travelled further East to remote areas constantly in search of gemstones of great color and beauty.

His endeavours to promote colored gemstones took him to Japan and Hong Kong, where he was joined by Jane Chung. Jane continues to guide the next generations in this family enterprise. Max explored mines in Africa and Brazil, and brought his finds to markets across the world, setting up offices in Japan, Hong Kong, Bangkok, Antwerp, Switzerland, New York and London.

Today the company is based in London and run by Maurice and Michael, his son and grandson. Together, father and son carry on the Ostro family legacy of passion and appreciation for these most exquisite colored gemstones.

The company has the world’s largest known, deep blue colored topaz gemstone. It weights 9,391 carats and is known as The Ostro Stone.


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