Blue and green are probably the most subjectively variable colours on the visible light spectrum. Last week a friend shared this quiz with me called, Is my Blue Your Blue which compares your perception of blues and greens against others. In particular it will help you know if you see the enigmatic colour turquoise as… Continue reading Blue, green, teal and turquoise
Author: Tehmina Goskar
Homage to August’s peridot
There is a tipping point around mid-August (in the Northern hemisphere north of the tropics) where the air starts releasing a dew-like moisture carrying the scent of the earth and beaches. The time of humid earth evokes the qualities of Virgo, a time to check the health of home, garden and self, to start organising… Continue reading Homage to August’s peridot
Laser ruby
As July draws to a close the glowing warmth of a ruby is somehow mirrored by stunning summer sunrises and sunsets. The dance that light does in and out of different gemstones changes according to the light source, and I feel that sunlight in rubies create an intensity and complexity of colour that few other… Continue reading Laser ruby
Should you rub pearls against your teeth?
It’s difficult to get through June without thinking of pearls. Pearls are one of June’s birthstones, together with moonstone and Alexandrite (a form of colour change chrysoberyl). This is an adaptation of a post I made during my Gem-A Gemmology Foundation course in 2022 on pearls. Last on, first off Things I remember being discussed… Continue reading Should you rub pearls against your teeth?
Magic gems in St Edward’s Crown
A year ago, during the build up to King Charles III’s coronation on 6 May 2023, there was intense coverage of the Crown Jewels and how they would be used in the liturgy of the Coronation itself. I became fascinated with St Edward’s Crown–the diamond-less crown that is only used once in a monarch’s reign–and… Continue reading Magic gems in St Edward’s Crown
Emerald month of May
Have you noticed the emergence of all things green of late? We move from the crystalline kaleidoscope filled month of April to the bright yellow-green gild of new oak, hazel and beech leaves at the start of May. From spark, fire and light we float back to earth and emeralds begin to loom large in… Continue reading Emerald month of May
Rock crystal: April’s other birthstone
Rock crystal is beautiful, powerful and has been used in adornment for thousands of years. It is April’s less famous, but no less beguiling, birthstone. My birthstone for April is diamond or rock crystal. I remember finding this out when a child and being quite pleased, thinking diamonds are expensive! Somehow I thought that caché… Continue reading Rock crystal: April’s other birthstone
Heamatite in quartz
I love haematite (also spelled hematite). This iron oxide mineral is the original mirror, having a highly polishable metallic lustre (while also dull and earthy in rough form), usually greyish-brown to silverish-grey to nearly black, and an inner core of blood red, hence the name. Haematite crystallises in the trigonal crystal system, the same as… Continue reading Heamatite in quartz
Colour in gemstones: quick notes
Some useful hand notes to distinguish terminology used to describe the optical effects that cause colour and colour phenomena in gemstones. It’s important to know your spectral colour effects like fire and iridescence and distinguish between pleochroism, iridescence and colour change. The cover image shows the two body colours (dichroism) that combine in a ruby:… Continue reading Colour in gemstones: quick notes
Spinel: quick notes
The lesser-sung cousins of corundum like sapphires and rubies, spinels are resilient gemstones that come in a variety of colours from greys and purples to ‘Jedi’ red. Here are some quick geological facts to get you started with this beautiful gem material. Note: Don’t get confused with synthetic (lab grown) spinel, commonly coloured blue with… Continue reading Spinel: quick notes