Gemstones

[shaggy1967]

Whar does topaz, garnet, aquamarine and turquoise have in common

[theprof]

Well, the simplest answer might be that they are all birthstones, but I appreciate this may not be the answer you require.

As a group, they are not chemically related to one another nor do they have similar hardness properties.

It's getting late so I think you'll have to wait for a better answer!

[wildwood]

Topaz, garnet, aquamarine and turquoise are all colours?

[north star]

all semi-precious stones ?

[terambulan]

all agates?

[rover123]

A blue to blue-green mineral of aluminum and copper, mainly CuAl6 (PO4) 4(OH) 8�4H2O, prized as a gemstone in its polished blue form.
they all have the same chemial coposits of copper

[gumboil]

Err, sorry rover123 but there are those of us on here who haven't a clue what you mean by by "they all have the same chemial coposits of copper "
Could you translate it into English please?

[theprof]

rover123 the first sentence of your post provides us with a physical description and formula for turquoise. The formula is irrelevant to the other three semi-precious stones.

Yes, they are all colours and semi-precious stones.

Agates are all forms of chalcedony (fine grained quartz) which are characterised by bands or zones that differ from one another in colour. Chemically, all agates are silicon dioxide.

Topaz is a form of hydrous aluminium fluorosilicate. Garnet is a complex double silicate mineral composed of calcium, manganese, magnesium and ferrous compounds combined with aluminium chromium and ferric ions. Aquamarine is a form of the mineral beryl.

[Ice.Maiden]

They're from the beryl family?

[theprof]

No, Ice.Maiden they are not all from the beryl family.