Ammolite originates from pre-historic marine fossils dating back almost 71 million years ago. It got the official status of a gem in 1981 by the World Jewellery Confederation. It is a gemstone which is cut from fossilized shells of extinct ammonites which were ancient sea creatures. These ammonites are mainly made of aragonite. Currently, the only mining of the gemstone is done is a small region in Alberta, Canada.
Today, ammonite is celebrated all over the world for its different layers of vibrant iridescence and rainbow colours. This makes it a naturally captivating organic gemstone. Many Feng Shui experts consider it as an “active” gem and believe the colourful display has numerous positive effects for individuals. It has many other names it is called by including gem ammonite, aapoak, calcenite and korite. Although it has been used for many generations by Native Americans, its been recently making its mark in the commercial jewellery industry.
We have provided a complete guide to ammolite to help you understand the gemstone better.
The amazing colours visible on the gemstone are red, blue, yellow, indigo, violet, crimson, orange and green along with a few more. The microstructure of the aragonite is what causes the iridescence to occur in the stone, whereas other gemstones display colours by absorbing light. This makes it different from most of the other gemstones. The piled-up layer of the aragonite’s slim platelets causes light to bounce back, creating a beautiful mixture of colours. The beauty of the colours seen on the surface of the gemstone is amazing as nearly all the colours available on the colour spectrum is visible on it. However, there are specimens of ammolites which may only display a very limited hue of colours.
Every specimen of ammolite displays a superb iridescence of various colours that resembles opals very closely. It is this property which creates the beautiful colours visible across the surface of the gemstone. The surface of these fossil shells is made up of tubular crystals of aragonite that are closely packed together. The c-axis is vertically oriented to the surface of the shell. The tiny crystals of aragonite align and form a plate-like structure. Its thickness is very close to the wavelength of white light. Due to this, a captivating play of colours appears in the gemstone. The greater the iridescence visible, the more value the gemstone will have.
- Chromatic Shift
People looking at these stones can witness a change in colours as they are rotated. Low-grade ammolite is usually monochromatic. This means that there is only a slight change when rotating the stone, usually from a pure green to a slight lime green. However, mid-grade ammolite will exhibit a drastic change of colour, typically from yellow to red which is known as dichromatic. High-grade ammolite has a spectrochromatic shift and is capable of showing very prominent colour changes along with an abundance of transitional hues.
- Clarity and Lustre
Ammolite gemstone is naturally opaque in nature. All of its specimens include a part of the host medium, typically shale, limestone or clay. It has a glass-like structure and can appear to be slightly resinous when it is stabilized with resins, polymer or epoxy.
Ammolite is a rare gem recently gaining popularity. Continue to Part-II of the blog post to find out more about the gemstone.