A gemstones

Sieber Agate

is a glass-type material that's a by-product of copper smelting in Germany. Hardness 6

Ammolite

Fossilised ammonite shell, may be stabilised with resin or offered as a doublet or triplet to improve durability. Hardness 4

Andalusite

Natural gemstone. Hardness 7.5

Andesine

Natural gemstone - a variety of feldspar. Hardness 6

Angelite

Natural gemstone. Hardness 3.5

Astrophyllite

Natural gemstone. Hardness 3, brittle and has perfect cleavage 

Atlantisite (serpentine and stichtite)

Natural gemstone. Serpentine hardness 2.5-5, stichtite hardness 1.5-2

Blue John

Variety of fluorite only found in Derbyshire, UK. 

Brittle and usually impregnated with resin to help bind it together. Hardness 4

Bowlerite

is cut from the outer skin of vintage bowling balls. 

Bridewell stone

is a manmade stone. Hardness 6.5-7

Bridewell stone

is a manmade stone. Hardness 6.5-7

Bronzite

Natural gemstone. Hardness 5.5

Calcite & scheelite

Natural gemstone. Scheelite has a hardness of 4.5-5, calcite has a hardness of 3 

Charoite

Natural gemstone. Hardness of 5-6

Chiastolite

Natural gemstone. Hardness of 6.5-7.5

Chrysoberyl

Natural gemstone. Hardness 8.5

Chrysoprase

Natural gemstone. Hardness of 6

Danburite

Natural gemstone. Hardness 7-7.5

Demantoid garnet

Natural gemstone. Hardness 6.5

Diaspore (Csarite or Zultanite)

Natural gemstone. Hardness 6.5-7

Dumortierite in quartzite

Natural gemstone. Hardness 7

Eudialyte

Natural gemstone.

Hardness of 5-6

Feldspar with ilmenite inclusions

Natural gemstone.

Hardness of 6

Fire agate

Natural gemstone.

Hardness of 5-7

Firecracker or Firework obsidian

Natural gemstone.

Hardness of 5-5.5

Fordite, ‘Motor agate’ or ‘Detroit agate’

is layers of vehicle paint that have built up and been baked on spray booths at motor plants.

Fossilised Dinosaur bone

Natural gemstone.

Hardness of 6-7

Fuchsite

Natural gemstone.

Hardness of 2-3

Goshenite

Natural gemstone.

Hardness of 7.5

Grandidierite

Natural gemstone.

Hardness of 7.5, brittle

Heliodor

Natural gemstone.

Hardness of 7.5

Hemimorphite

Natural gemstone. Hardness of 4.5-5 & brittle

Hessonite garnet

Natural gemstone.

Hardness of 7.25

Hornblende and garnet

Natural gemstone.

Hardness of 5-6

Hypersthene

Natural gemstone.

Hardness of 5.5-6