Wondering what’s the difference between agate and carnelian? These two popular gemstones could look very similar, but there are some key differences. By the end of this article, you'll know exactly how to tell agate and carnelian apart.
Let's start with the basics. Agate and carnelian are both forms of chalcedony, which is a microcrystalline type of quartz. Chalcedony is found in rocks around the world and is made up of tiny quartz crystals.
What is Agate?
Agate is a form of chalcedony that has colour banding. The banded gemstones come in all sorts of colours like grey, blue, brown, pink or the colours that get confused with carnelian - red and orange. Agates form when mineral-rich water flows through tiny cracks and holes in rock. As layer upon layer of chalcedony deposits build up, those neat bands are created.
Agates are often named after the places they are found, like Montana Agate or Botswana Agate. But other types are labeled based on appearance, like Blue Lace Agate or Moss Agate. No matter the colour patterns though, all agates by definition must have visible banding to qualify as an agate.
What is Carnelian?
Carnelian is a solid red-orange variety of chalcedony. Unlike agate, carnelian does not display banding. There are sometimes colour variations within the gemstone. It has a consistent red-orange hue. Its colour comes from trace amounts of iron oxide minerals that are present when it forms.
Carnelian has been used since ancient times for decoration and jewelry. Some ancient cultures like the Egyptians and Romans also admired carnelian for its bright orange shade, which resembled the warmth of a fire.
The Difference Between Agate and Carnelian
Agate has colour banding, carnelian doesn’t. Usually carnelian has a consistent red-orange colour throughout the gemstone
Agate has a wide range of possible colours. Carnelian is always red-orange.
So the takeaway is: Red agate is a red coloured agate is a banded chalcedony, while carnelian is solid red-orange chalcedony without banding. Now you should be able to tell the two popular orange gemstones apart!