There are a huge variety of natural gemstones regularly used in jewellery.
Most are minerals of some kind, the definition of a mineral being that it is solid and stable at room temperature, and that is has an ordered atomic structure (very scientific!)
There are a few exceptions to this, lapis lazuli is a rock, and there are organic materials such as amber and pearls which are often considered to be gems.
The different colours of the minerals come from differences in their structure, which affect which colours of light they reflect. Some stones can be heat treated to change their colour.
We tend to associate the names of gemstones with their colour, but in many cases the different colours of the same mineral have different names.
As an example, rubies and sapphires are technically the same type of mineral, all colours of corundum except for red are referred to as sapphires. Sapphires are most known for being blue, but come in all kinds of beautiful colours.
Diamonds are generally expected to be clear, but also appear naturally in lots of different colours from pink and yellow to blues, browns and greens. Sapphires and topaz also have totally clear forms which before synthetic gems were developed were used as diamond substitutes.
The cost of stones is affected by their rarity and popularity. Traditionally stones were divided into precious and semi-precious, with diamond, ruby, sapphire and emerald being precious stones.
More recently this division is less important, although these stones are probably still some of the most popular and well known.
Gemstones can have natural inclusions, other materials or flaws within the stone which are a different colour. In something like a perfectly clear diamond these make the stone less valuable, but with other types of stones they can create very interesting effects.
The most known stones and colours are generally the most expensive, but there are generally different grades. The deeper and richer the colour of an emerald, the more expensive it will be. A paler stone, possibly with inclusions will be less expensive.
Garnet and smoky quartz
All my stone set rings are available with a variety of different stones, if you have something specific in mind send me an email for options. I could also source a special stone to be the centre of a bespoke piece.