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Gem of the Month: Agate

The modern and traditional birthstone for September is Sapphire – covered in a previous article.  While sapphire is our primary interest, we also enjoy and appreciate the many alternative birthstones for each month.  The mystical birthstone for September is Agate – a stone of amazing variety and colour.

Gemmology Matters:  Agate is the name given to a very large family of quartz gemstones of which Sardonyx – subject of our last Gem of the Month article – is a member.  Agate is a type of chalcedony or fibrous cryptocrystalline quartz (SiO2) and is found in a variety of colours, may be translucent, transparent or opaque and has a hardness of 6.5 to 7.

Agate used for ornamental or in jewellery is often treated by dying to enhance or alter colour.  Since quartz is a very abundant mineral on Earth, agate is quite inexpensive.  Some particularly attractive and unusual varieties may command a higher price but this stone is still a great way to start an affordable gem collection.  Moss agate and Plume agate are two varieties which are priced higher due to beauty and demand.

Agate is found throughout the world in a huge variety of form.  Probably every country has a particular area that yields stones of a particular type of beauty and Australia is no exception.  Here in Queensland, there is an area (surprisingly called “Agate Creek”) which is rich in these gems which are available for anyone to find for just the price of a fossicking licence and a few hours of digging.

Mythology and Lore:  The name agate derives from the Greek for stones found on the Achate river in Sicily.  Agate has been used for thousands of years – examples have been found with other Stone Age relics dating back to as early as 20,000 BC.  Agate was also used by early civilizations for talismans, amulets, seals, rings and vessels.

People in medieval times wore agate to bring God’s favor, enhance persuasiveness, increase courage and strength and protect against danger.  Agate was also used to promote pleasant dreams and cure insomnia.  Early Greeks made amulets of agate for protection from the elements of the sea.

Agate is associated with the zodiac sign of Gemini and for those born in the month of May.  Agate may also be given to celebrate the 12th wedding anniversary.

qldagate1.jpgAlternatives for Agate:  Due to the extremely wide variation in colour and form, there is really no alternative for this unique gem.  Added to this, the fact that it is very affordable, there is no excuse for you not to have at least one attractive piece in your collection.

Links of Interest:

  • Bernardine Fine Art Jewelry – article on Agate
  • Mineral Miners – Fact sheet on Agate
  • Wikipedia article on Agate
  • Agate on Mindat.org – Minerals Database
  • Agate Creek area – Australian Gem Gallery
  • Fossicking information for Agate Creek – Queensland

Cheers for now from Aussie Sapphire

And remember, if you are looking for the traditional September birthstone of sapphire, we can give you lots of choices in our online shop.


  1. Ping from Pete Anderson:

    I just have to toot my horn for our local (Minnesota USA) form of agate, Lake Superior Agate. It often is characterised by alternating bands of rich red and white. Most are really beautiful and all are unique. Other colors occur as well depending on the minerals in solution when the agate was formed. Pink, green, blue (rare), orange, yellow, blood red. Another less common, though not rare, feature are called ‘eyes’. I don’t know how these form (bubbles?) but they are mostly perfectly round and very well defined. I have some eye agates that are among my favorites. The red color predominates. The area near Lake Superior is rich in iron ore and it is from this that much of the red color derives.

  2. Ping from aussiesapphire:

    Thanks for your message – agate certainly is fascinating for the incredible variety of colour. Each area produces stones with a unique beauty. If you have some good photos, would have happy to include them in with your information so others can appreciate them also.

    cheers from Aussie Sapphire