Gold And Platinum Minerals
Gold is yellow- gold colour and streak and metallic lustre, combined with its soft (H 2.5-3) and very dense (SG 15.6-19.3) nature are characteristic Crystals (cubic) are easy damaged due to their malleable nature. Novices may confuse flecks of other yellowish minerals with gold, The so-called ‘Fools Gold’ Mineral-Pyrite, chalcopyrite and altered mica.
Gold Crystals in Quarts.
Gold Forms Crystals, but well formed crystals are uncommon. Octahedral shapes are typical, but there are also rounder, wiry, branching, leafy, mesh like or even skeleton shapes. Flattened scales and grains are common, sometimes occurring in thin sheets.
Australia gold fields are world famous, Particularly the historic Victorian and Kalgoorlie ” golden Mile”, Western Australia fields.
Chalcopyrite Peacock Ore
Gold Nuggets. Gold Nuggets Do Not Like to Be Lonely.
Because of its density, released gold often concentrates near its source ( eluvial gold) or will wash further away (alluvial gold). Some gold is deposited from ground waters in soil horizons to form irregularly shaped nuggets.
Alluvial Gold (Deposited by water movement)
Eluvial gold (disintegration of rock at the site where it originates – not there through water movement are essentially primary gold broken down by weathering and erosion and transported by gravity or water movement over many millenia of geological time
Calaverite Gold.
This rare gold, Tellurium mineral appears in the classic Kalgoorlie Ore. It is a silver-white colour, often with a yellowish tinge. Small like crystals (Monoclinic) occur, but granular to crystalline masses are typical..
Krennerite.
Krennerite and Sylvanite are rare gold and silver, tellurium minerals and both appear in Kalgoorlie Ores. Krennerite is silver-white to brassy-yellow in colour. Crystals often form prisms (orthorhombic) with perfect cleavage. They are soft (H2.5) and heavy (SG over 8).
Platinum Minerals.
These are often associate with silica-poor rocks, but are rare. Platinum forms grains, scaly crystals (cubic) and nuggets. Its steel grey, metallic colour, moderate hardness (H 4-4.5) and high density (SG 14-19) are distinctive.
Due to its rarity, platinum is more highly priced than gold or silver.
Platinum is more expensive than gold, approximately twice. Its price changes along with its availability. In the 18th century, the rarity of platinum made King Louis XV of France declare it to be the only metal fit for a king.
Yellow Gold
So, what’s the difference between 9ct and 22ct gold?
Here’s how they are broken down:
- 24 carat gold
- is the ultimate gold carat – it doesn’t go any higher than this. It’s the purest form and consists of 99.9% gold. It is naturally yellow and highly valuable, but very soft and malleable, so it is not usually used to make fine jewellery or intricate objects.
- 22 carat gold
- consists of around 91.6% gold and so is highly priced. It is also very soft, so it’s not ideal for stone set jewellery, being more suitable for plain gold jewellery, such as wedding bands.
- 18 carat gold
- contains 75% gold, with the rest made up of other more durable metal alloys used to add colour and strength. White metals will be added to create white gold with copper added to create rose gold. 18ct yellow gold is appreciated for its radiance and is much warmer and brighter in tone than 14ct and 9ct gold – but with its high percentage of gold, it still comes at a higher price.
- 14 carat gold
- has about 58.5% pure gold and has a warm yellow hue. It is more affordable than 18ct gold, making it a popular choice.
- 9 carat gold
- has 37.5% pure gold; it is the most affordable form of gold jewellery and portrays a light yellow hue. Its higher percentage of other metals, makes it stronger and more durable and particularly suited to the creation of jewellery.
White gold vs. platinum
- Is white gold the same as platinum?
- White Gold.
Is white gold the same as platinum?
The answer to this question is no. White gold and platinum have their own properties which make them unique. The following white gold information and platinum information show you the difference between the two metals.
You will discover the difference between white gold and platinum and whether white gold or platinum is best for your needs.
White Gold
White gold is an alloy of gold and some white metals such as silver and palladium. White gold can be 18ct, 14ct, 9ct or any karat. For example, 18ct yellow gold is made by mixing 75% gold (750 parts per thousand) with 25% (250 parts per thousand) other metals such as copper and zinc. 18ct white gold is made by mixing 75% gold with 25% other metals such as silver and palladium. So the amount of gold is the same but the alloy is different.
Traditionally nickel was used in white gold, however, nickel is no longer used in most white gold made today as nickel can cause reactions with some people.
When white gold rings are new they are coated with another white metal called Rhodium. Rhodium is a metal very similar to platinum and Rhodium shares many of the properties of platinum including its white color.
The rhodium plating is used to make the white gold look more white. The natural color of white gold is actually a light grey color. The Rhodium is very white and very hard, but it does wear away eventually. To keep a white gold ring looking its best it should be re-rhodium plated approximately each 12 to 18 months.