Minerals as Crystals

Nearly all minerals grow in certain crystal forms. They are homogeneous bodies with a regular lattice (inner structure) of atoms, ions, or molecules geometrically arranged, and their outer shapes are limited by flat surfaces, resulting in crystal faces.

A MINERAL is defined as a naturally occurring inorganic solid with a definite chemical composition, and an ordered atomic arrangement.

A mineral's chemical composition and lattice determines the physical properties of the crystal: outer shape, hardness, cleavage, type of fracture and specific gravity or density) along with opitical properties (color, streak, refraction of light, light/color effects or luminous and inclusions).

A CRYSTAL HABIT is the arrangement of crystal faces and type: 

     • Tabular

     • Acicular

     • Foilated

     • Columnar

     • Compact

For more crystal habits: 

https://en.m.wikipedia.org/wiki/Crystal_habit

Twins, Triplets or Quadruplets refers to when two or more crystals are intergrown.

Twinning is when two crystals are grown together (Contact Twins) or intergrown (Perpetual Twins).

Apart from twinning, many crystals are intergrown irregularly into aggregates depending on their growth process:

     • Filiform 

     • Fibrous

     • Radial-Shaped

     • Leaf-Like

     • Shell-Like

     • Scaly

     • Grainy

Druse or Druzy is a glittering effect of hundreds of tiny, fine crystals on a rock fracture surface, vein, or within a geode.

Crystal Systems are dependent on the crystal's axes and angles at which the axes intersect.

     • Cubic or Isometric: all three axes have same length and intersect at right angles. 

Typical shapes: cube, octahedron, thrombic dodecahedron, pentagonal deodocahedron, iconic-tetrahedron and hexacisochedron.

     • Tetragonal: three axes intersect at right angles with two being the same length on the same plane while the main axis is either longer or shorter. 

Examples: 4-sided prisms, pyramids, trapezohedrons, 8-sided pyramids and double-sided pyramids.

     • Hexagonal: 3 of the 4 axes are in one plane, are of the same length and intersect each other at angles of 120 degrees. The 4th axis which is of different length of the other 3 axes is at right angles to the others. Cross-section: 6-sided.

Examples: hexagonal prisms/pyramids, 12-sided pyramids and double-sided pyramids.

     • Trigonal: same as hexagonal, except in symmetry. Cross-section is 3-sided.

Examples: 3-sided prism/pyramid, thrombohedra, and scalenohedra.

     • Orthorhombic: 3 axes of different lengths are at right angles to each other. 

Examples: basal pinacoids, rhombic prisms/pyramids, and rhombic double pyramids.

     • Monoclinic: 3 axes, each of differing lengths with 2 at right angles to each other, and 3rd axis is inclined.

Examples: basal 

pinacoids and prisms with inclined end faces.

     • Triclinic: all 3 axes are different lengths and inclined to each other. 

Example: paired-faced crystals.

Crystal Cleavage 

Cleavage refers to the tendency of crystalline materials to split along definitive crystallographic structural planes. Depending on the ease of which a crystal can be cleaved differentiates between perfect, good, or imperfect. Some gemstones cannot be cleaved at all, and therefore have no cleavage.

Crystal Parting occurs when minerals break along planes of structural weakness due to external stress or along twin composition planes.

A Fracture is the breaking of a gemstone with a blow, producing irregular surfaces: conchoidal (shell-like), uneven, smooth, fibrous, splintery and grainy.

Optical Qualities 

     

     • Color

     • Streak

This is the color of a crushed mineral or its powder. The color of the mineral can be different than the powder. This streak is used to distinguish two minerals with the same color. 

Instead of crushing a mineral to detect its streak color, a streak plate is used. The streak plate is an unglazed piece of ceramic tile that is light in color. The mineral is swiped across the streak plate. 

If a streak is colorless, it is sometimes referred to as white. Although white streaks are also referred to as white.

     • Transparency

The transparency of a mineral is either translucent or opaque, and can be seen with the naked eye, using a powerful (strong) light source. If the light passes through the mineral, it is translucent.

     • Luster

Light and Color Effects

Many gems show striated light effects which do not relate to their body-color, and are not caused by impurities, or their chemical composition. The effects are caused by reflection, interference, or refraction.

     • Adularescence is an interference phenomena of the layered structure of the mineral or gem.

     • Asterism is the effect of light rays meeting at one point and enclose definite angles depending on the symmetry of the stone, causing a star to appear.

     • Aventurescence is the colorful play of glittering reflections of small plate or leaf-like inclusions, caused by the stone containing hematite or goethite.

     • Chatoyancy is caused by the reflection of light by parallel fibers, needles, or channels. (Cat's Eye)

     • Iridescence is caused by cracks or structural layers breaking up light into spectral colors (rainbow-like hues).

     • Labradorescence is iridescence in metallic hues (also known as Schiller) and is probably due to lattice distortions accompanying alternating microscopic exosolution lamellae.

     • Opalescence is a milky-blue or pearly appearance caused by the reflection of short waves, mainly blue light.

     • Orient is created through diffraction and interference of light by shingle-like layers of aragonite platelets near the pearl's surface.

     • Silk is the reflection of fibrous inclusions or canals causing a silk-like appearance in faceted rubies and sapphires. 

#CrystalHabits #CrystalStructure #WhiteColorStreak #Luster #Cleavage #Fracture

    

Igneous Rocks

This blog is about igneous rocks as I was researching Amazonite and found that I know very little about rocks and minerals.

Igneous rocks form from the solidification of molten rock material. There are two types of igneous rocks: intrusive and extrusive. The word, "igneous" is derived from the Latin word, 'ignis', meaning fire.

Intrusive Rocks are crystallized magma under the earth's surface that slowly pushes upwards, filling any cracks or spaces it can find. (This process takes millions of years to complete.) As the rock slowly cools into a solid, different parts of the magma crystallize into minerals.

     • Diorite:

is a coarse-grained rock that contains feldspar, pyroxene and hornblende, plus sometimes it also contains quartz.

https://en.m.wikipedia.org/wiki/Diorite

     • Gabbro: 

is also coarse-grained, along with being dark in color and contains feldspar, pyroxene, and sometimes it also has olivine.

https://en.m.wikipedia.org/wiki/Gabbro

     • Granite: 

is coarse-grained as well, but is light colored and is comprised mostly of quartz.

https://en.m.wikipedia.org/wiki/Granite

     • Pegmatite:

is extremely coarse-grained and forms near margins of magma chambers, during the final stages of crystallization in the magma chamber. Pegmatite is composed of rare minerals (such as: microcline) that are not found in any other parts of the magma chamber.

https://en.m.wikipedia.org/wiki/Pegmatite

A magma chamber is a large underground pool of liquid rock beneath the earth's surface. This molten rock is under great pressure and given enough time, this pressure can gradually fracture the rock around it causing a volcanic eruption. 

https://en.m.wikipedia.org/wiki/Magma_chamber

     • Peridotite:

is coarse-grained and comprised entirely of olivine, may also contain minute amounts of amphibole, feldspar, quartz or pyroxene.

https://en.m.wikipedia.org/wiki/Peridotite

Extrusive Rocks form when hot magma from inside the earth flows out onto surfaces as lava, or explodes violently into the atmosphere to fall back as pyroclastics or tuff. The main effect is that the magma cools quickly in open air or in seawater with very little to no growth of crystallization.

     • Andesite:

is fine-grained and comprised mostly of plagioclase with other minerals (hornblende, pyroxene and biotite.)

https://en.m.wikipedia.org/wiki/Andesite

     • Basalt:

is also fine-grained but dark in color and is composed of plagioclase and pyroxene.

https://en.m.wikipedia.org/wiki/Basalt

     • Obsidian:

is dark colored volcanic glass formed from the very rapid cooling of molten rock material, with absolutely no form of crystallization.

https://en.m.wikipedia.org/wiki/Obsidian

     • Pumice:

is light in color and has a vesicular texture which is caused by gas trapped in the melt at time of rapid solidification.

https://en.m.wikipedia.org/wiki/Pumice

     • Rhyolite:

is also lightly colored and fine-grained, typically contains quartz and feldspar materials.

https://en.m.wikipedia.org/wiki/Rhyolite

Fire Opal can be found in cavities of rhyolite. Long after rhyolite cools, silica-rich groundwater moves through the rock depositing gems like opal, red beryl, topaz, jasper or agate.

https://en.m.wikipedia.org/w/index.php?title=Opal&redirect=no

     • Scoria:

is dark in color and also has a vesicular texture that often forms a frothy crust on top of lava flow or as material ejected from a volcanic vent and solidifies while airborne.

https://en.m.wikipedia.org/wiki/Scoria

     • Tuff: 

is composed of materials ejected from a volcano, fell to the earth and then lithified into rock. It is composed of mostly volcanic ash and sometimes contains cinders and other large-sized materials.

https://en.m.wikipedia.org/wiki/Tuff

The other two types of rocks are:

     • Sedimentary 

http://geology.com/rocks/sedimentary-rocks.shtml

     • Metamorphic

http://geology.com/rocks/metamorphic-rocks.shtml

#IgneousRocka #IgneousRock #Geology #IntrusiveRocks #ExtrusiveRocks

Basic Tools for Jewelry Making

A gal asked me if I had any tips on tools, supplies and the like for creating jewelry, and I thought to myself, 'Huh, this would make a great blog topic.'

So before I begin talking about the basic tools for jewelry making, I thought it might be nice to go over the actual anatomy of pliers...

Pliers can be made with differing types of steel along with different types of joints. The most important aspect of the pliers will be the construction: this will tell you the quality of the pliers. 

     CONSTRUCTION 

     • Forged is the highest quality you can get. These type of pliers are forged from a rod of tool steel and are work hardened as the metal is compressed and shaped. Then the pliers are tempered to prevent brittleness and produce the best combination of durability and strength. 

     • Cast: these pliers are formed in a mold made from molten metal and are not tempered.

     • Stamped: these type of pliers are made from a sheet of metal; they're the cheapest in both cost and quality.

     JOINTS

     • Box: 

     One half of the pliers joint surrounds the other half, and the pivot is hidden within. This type of joint holds alignment far longer than a lap joint but limits the opening of the jaws.

     • Lap:

     A lap joint has one half of the pliers joint overlapping the other half, and a pivot or screw is set through both halves.

     HANDLES

     Did you know that when you grip a pair of pliers, you are using over 40 muscles? That's a lot of muscles at work! It is imperative to get pliers with ergonomic handles so that they conform to the shape of your hand. I'd recommend getting pliers that have either soft plastic or foam handles.

     COMPOSITION 

     High-carbon or high-chrome alloy steel is the highest quality steel that produces the longest-lasting pliers and cutters. Yes, they are priced more significantly than hardened tool steel, but they are worth it! Stainless steel is also of good quality and will have a reasonable life.

     Here is a great link that describes pliers to the hilt: http://www.silversupplies.com/catalog/tools/pliers/

O.K. on to the basic tools for jewelry making which are: round and flat nose pliers plus flush cutters; optional are bent chain nose pliers. Then we have rulers, tape measures, Sharpies, and more.

3-in-1 or 4-in-1

If you are just starting out and want to save some money for supplies, or you are unsure of the type of jewelry you will make, or this is a hobby - BUY yourself some 3-in-1 or 4-in-1 pliers. These are inexpensive and will last awhile. I bought a pair of 4-in-1 pliers which are round/flat nose, cutters and have a groove to close jump rings.

These pliers lasted me years, and I still keep them around just in case.

ROUND NOSE PLIERS 

Round nose pliers have tapered jaws from pivot to tips. These are used to make various loops, S-hooks, jump rings, clasps, coils/spirals and curved bends, plus to form headpins and eyepins.

You will use this type of pliers the most, and despite what other sites say - I'd highly recommend buying the highest quality you can afford. I bought cheapie round nose pliers (according to so many people's recommendations.) Let me tell you - the cheap ones' tips dont match up, and this makes it extremely frustrating!

There are standard and long round nose pliers that you can get. The standard ones, you will use on a regular basis. The long round nose pliers are used to make coils. The longer the jaws on any type of pliers, the less control you have.

High-quality pliers to look for: Swanson (Rio Grande), Lindstrom, Wibbers, OHM and Euro Tool.

FLAT NOSE PLIERS 

Flat nose pliers have a flat interior surface inside the jaws and are used to hold components, open/close jump rings, make angular bends in wire and also to straighten and strengthen wire. Plus with flat nose pliers you can make spirals and close crimp covers. These also come in standard and long as well as narrow and wide. I have several types and use them for different applications.

CHAIN NOSE PLUERS

If you will be doing a lot of chain mail work, you should definitely invest in straight chain nose vs. bent chain nose pliers. 

With chain nose pliers, both jaws are semi-round with flat interior surfaces and taper at the end. They are used for holding components, opening and closing jump rings, and reaching into tight places. The tips on the bent chain nose pliers are angled, and these are perfect for holding wire when you wrap so you can see what you are doing.

I didn't buy bent chain nose pliers for a long time because I never really used the straight ones for anything. After I bought a pair of these, I cannot even fathom wire wrapping without them!

CUTTERS

The ones on the bottom are Lindstrom that were destroyed because I cut memory wire with them. The red handled flush cutters are from Ace Hardware and are of good quality. The cutters with the royal blue handles cut up to 14ga wire and metal.

Oh the joy of cutting! There are several types of cutters out there - definitely buy the highest quality you can afford! AND do NOT use them to cut memory wire!!!! Let me repeat that: DO NOT USE ANY TYPE OF CUTTERS other than Memory Wire Shears to cut memory wire. You will dull the cutters very quickly after one single use of cutting memory wire. 

Memory wire is a type of steel wire that retains its shape. You can only use Memory Wire Shears to cut this type of wire!

I have bought so many cheapie cutters over the years because I didn't want to invest $50.00 into a good pair of cutters... and then when I finally broke down and bought a pair of Lindstrom flush cutters - I used them to cut memory wire. Oh my golly gee - what a waste of $$$! I've never been able to use them again! The blades don't match up even though I had the blades sharpened. *sigh*

     • FLUSH cutters, also known as SIDE cutters: the jaws are pointed and angled, almost parallel to the handles. If you don't want a bur on the end of your piece of wire, you need to turn the pliers around so that the straight edge is away from the section of wire you are cutting. If you don't want to deal with this bur, buy a pair of super flush cutters.

     • END cutters: these type of cutters have blades perpendicular to the handles and provide more cutting leverage. Use these to make sharp, clean cuts close to the surface of wire.

The shears on the left are Memory Wire Shears and the cutters on the right are End Cutters.

     • OBLIQUE cutters: a type of end cutters that feature an angled head to allow you to cut hard-to-reach areas. Only use these to cut softer metals.

     • COMPOUND cutters: these are designed with two joints to maximize hand power when cutting thicker, heavier metals.

RULERS and TAPE MEASURES 

Make sure to have some of these handy. I'd get a metal ruler, a see-through ruler and of course a tape measure. Also look for rulers with standard and metric, preferably going in the same direction. Most rulers have these two but inches are left to right and centimeters is right to left. 

I have rulers - metal, see-through, tape measures and a sticky ruler. The latter being on a roll, and I just pull off 12" and stick it to my workbench. I absolutely love this type of ruler!!! 

SHARPIES or other PERMANENT MARKERS 

I know it seems weird but Sharpies are magnificent tools! You can use them to mark the tips of your round nose pliers so that you can make consistent loops and also use them as a mandrel. 

BEAD MAT

This, of course, is optional. A bead mat protects your work surface and also keeps beads and components from sliding around. 

#BasicToolsJewelryMaking #JewelryMakingTools #PliersAndCutters