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Gems and Ornamental Stones

As I mentioned before we will be spending the next 3-6 weeks on the sparklies - there is that much material

A: hears Semi moving into place for some "sparklies" to add to her hoard

What I propose to do is start at the bottom with the Ornamental and carving stones and move up to the precious gems and then the imitations ,fakes and such any problems with that?

A: not a one DH

P: Not a one :>

P giggles "GMTA" :> -->

EW: works for us

Ok gems are simply stones that are used for decoration because they are pretty :> Either for personal decoration or home decoration They fall into 2 main groups - the decorative/ornamental/carving stones and the gems - there is a large area of overlap in the fancy or cabochon stones however. Carving stones are (relatively) soft making them easy to carve and polish - however this also means that they are easy to scratch and mar. The real gems are generally harder making them more wearable - especially those used to make things like rings. In general we use quartz (H=7) as the dividing line between soft and hard minerals as it is the most common mineral at the earth's surface. Soft minerals are those that quartz scratches and hard are those that scratch quartz :>

Ornamental Gemstones

Ornamental materials are those used to create objects larger than jewelry but smaller than entire walls <G> . this includes inlay materials, statuary and figurines, carved objects and containers as well as any other items you might think of in that size range. In reality essentially every kind of colored or pretty rock or massive mineral has been used at least once. some of these materials are used in construction and as polished facing stones also but we aren't really considering them here - or at least we aren't considering such uses

[G]: decorated frames around mirrors?

yep G <G>

*A* what about the mythic "amber wall"

[G]: noted

The carving stones fall into 4 main groups - the Soft Stones, Organic Materials, Medium Stones and the Hard Stones.
Marble, alabaster (Gypsum) and soapstone (Serpentine) among others being the soft stones - all have a hardness of 3 or less.

Soft Carving Stones

The main soft stones are: Alabaster, Serpentine, and Marble, so lets look at them :>

Alabaster (and some onyx)
Is made from massive gypsum which has a hardness of 2 it normally forms white materials with a visible graininess. That is the texture that is desired - just large enough to be seen clearly without being so big as to make carving difficult while it is normally white it can be stained almost any color

[G]* is their another name for alabaster I can't find it in my references.. the closest I get is albite -->

Its the name for massive gypsum G - check under that

[G]: gypsum specific gravity 2.3-2.4


Ok alabaster - is soft so its normally used for objects that generally just sit and aren't subjected to wear and tear - or to inexpensive objects

Serpentine (A.K.A. soapstone) - it forms generally green to blue-green masses with other materials "marbled" in

[G]: serpi or serpen?


[G]: thank-you

serpentine actually can range from a dull grey or blue to rich greens

[G]: serpentine hardness 3-5 SG 2.5-2.6 monoclinic crystal structure

There are a number of similar or related minerals that I'm including under the heading serpentine - one of these is talc and as they are often found mixed together we can sort of ignore the differences for now

[Gh]: also nephrite..


I'll get to nephrite later

[G]: ok sorry... similar species

not quite

Like the other soft stones serpentine is used for statuary, figurines and decorative objects that aren't generally subject to much handling and abrasion.

The last two major soft stones are both carbonates - Marble and Rhodocrosite.

Marble is recrystalized limestone and dolomite. While it comes in a wide variety of colors and grain sizes the best marbles are considered to be the white statuary marbles with a "sugary" texture such as those found at Carrera Italy. Verde Antique is a greenish marble with inclusions found at several places in Italy and at Cardiff MD.

EW: sugary? I thought Marble was smooth?

Sugary because the grains are about the same size as those of sugar grains son

EW: oh ok thanks :>

When polished smooth they provide much of the sparkle P. A blue-white statuary marble is mined at Talledega AL and many other varieties are found and named mostly according to the patterns seen or colors or inclusions in them Marble deposits are found all along the western edge of the Appalachian Mts and around most mountain ranges world wide.

Among the minerals there are a number of other stones that are of low hardness and often carved though most are not carved with the frequency of those mentioned so far.

Rhodocrosite is Manganese Carbonate and forms a pink banded massive rock that is often turned int figurines or globes or other display objects. Rhodocrosite is unusual in the soft stones in that it is often also made into cabochon jewelry - this is because no other material has its coloration really :> In general only the harder ornamental stones are used to make jewelry for those who don't know - cabachons are the flat or round toped generally opaque jewelry stones and for this I'm including such other uses as beads as well. Some of the better sites for Rhodocrosite are: Alma CO, S Africa (Hotazel) and Argentina, (San Luis Catamarca Prov.)

Azurite and Malachite are carbonates of copper with Azurite being Blue and Malachite being green they are often found together and used together. While they can form crystals they are normally found in massive bodies and are often banded and intermixed in attractive patterns

They are also slightly harder than the other soft minerals (H: 3-4) and are used for jewelry and for a wide variety of objects from chess pieces to balls to cups. In some cases they have even been used to make columns and face walls (the Russian Winter Palace).

Sepiolite - better known as Meerschaum

EW: for pipes right?

Yes - It is white when first carved but absorbs tobacco juice and skin oils turning it first golden and then a dark brown and eventually black. I must have spent about 400-500$ on meerschaum pipes when I was smoking. because they absorb the tobacco juices the pipes produce a much milder flavor from the same tobacco - since you don't get it on your tongue this way :> Actually lets say mellower not milder.

T: where is meerschaum found?

T: in the wild that is?

The most important deposits are those at Esckischor Turkey, but other deports are found in Spain, Greece, Czechoslovakia, Morocco, and in Utah, California, Pennsylvania, and New Mexico.

G: and how difficult is it to carve?

As it has a hardness of 2.5 and is very finely granular its actually fairly easy to carve - or to ruin <G>

T: I think I would like to give carving a try sometime.

G: I'd like to try as well

T: I am not very artistic but a pipe might be interesting to make.

organic stones

There are 3 other soft ornamental materials but they are effectively organic not mineral - Ivory, Coral and Mother-of-Pearl - of these only fossil ivory and M-o-P are legal to trade today - though both coral and ivory are available :< Actually small amounts of both are still legal and this is part of the trouble.

T: Is mop expensive?

T: I have a full 12" shell

just a sec T :>

Mother of Pearl is organically produced aragonite plates - as such it is found in all shells so the general price is fairly low however, such things as abalone shell and certain other shell types (like Nautilus) that are rare or unusual are much more expensive

T: but abalone is valued more cause ? ok

Mother of pearl is normally used as inlay or for things like handles of knives or dinnerware since it forms in thin relatively flat shapes

A: pearls are in another category?

Pearls are the same material - but! and so we will consider them when we get to the precious gems where they have been classed historically.

Coral - generally red or black in color it is the dried colony of any of several varieties of medium to deep (15 to 100 Meters) sea corals . these corals form hard branching shapes and it is these branches that are cut and polished to form beads and jewelry or are carved or used as inlay .

Ivory is the teeth of several different animals - elephants, whales (toothed), hippos, and Walrus or their extinct predecessors like the mammoths

T: someone said elk had 2 Ivory teeth is this true?

welllllll your teeth are ivory technically. The thing that separates the real ivory from the others is really the amount of enamel and the overall size of the teeth :> yours aren't much good for carving and figurines

T: cool.

EW: didn't George Washington have ivory false teeth?

yes and wood ones

T: ivory for dances and wood for every day he he he

EW: lol gee splinters

Today almost all trade in ivory is illegal - the only legal ivory being fossil (mammoth) ivory and a little bit of legal ivory from Burma and Africa where it is provided by the governments. Unfortunately this provides a means of creating a black-market in the stuff :< Ivory was once used for things like piano keys, pool balls (especially the cueballs and for jewelry and many other items I have an antique piccolo that has an ivory mouthpiece.

T: I seen a whale tooth with a early ship with sails drawn on it. It was pretty cool but totally out of my price range.

Yes - such antique items are still available - sort of and there are countries where you an buy ivory and other organic materials legally - but exporting them to the US will get you in a world of trouble.

Medium Carving stones

Chrysocolla (hydrous copper-aluminum silicate) chrysacholla generally has a blue to green color and is intermixed with other materials to create interesting bandings

Variscite (aluminum Phosphate) - variscite generally has a blue to green color and may be intermixed with other materials to create interesting bandings

the finely granular micas

P: Ohhhh, micas :>

Fuschite - emerald green and rarely used made of chrome Muscovite

Alurgite - brick red - the manganese muscovite

Lepidolite - the lithium mica that is a brilliant lilac color

Glauconite - a green marine mica may be used occasionally also

Of these the most common by far is the lepidolite which is generally left unpolished so the flakes show their colors best

Other materials like the bright green nickel ore Garnierite have been used on occasion but are much less frequent.

OK - next week we will look at the Hard Ornamental Stones

Website created: January 22, 1998
Website last updated: October 11, 1998