Dr. H. L. Ong's Collection

Diamond

Mineral

Composition

C (Carbon)

Colors

Colorless, various

Hardness

10 (Hardest natural substance)

Varieties

Fancy, Yellow, Blue, Green, Pink, Red, Black

Diamond is the hardest known natural substance, widely used in jewelry and cutting tools.

Quartz

Mineral

Composition

SiO2 (Silicon dioxide)

Colors

Clear, white, pink, etc.

Hardness

Varieties

Amethyst, Citrine, Rose, Smoky, Milky, etc.

Quartz is the most abundant mineral on Earth, with many varieties and colors.

Corundum (var. Ruby)

Gemstone

Composition

Al2O3 (Aluminum oxide)

Colors

Red

Hardness

Varieties

None (Ruby is the primary variety)

Ruby is the red variety of corundum, highly valued for its vibrant color.

Corundum (var. Sapphire)

Gemstone

Composition

Al2O3 (Aluminum oxide)

Colors

Blue, various

Hardness

Varieties

Yellow, Pink, Green, White, etc.

Sapphire is a precious variety of corundum, known for its blue hue.

Beryl (var. Emerald)

Gemstone

Composition

Be3Al2(SiO3)6 (Beryllium aluminum silicate)

Colors

Green

Hardness

7.5-8

Varieties

Emerald

Emerald is a green variety of beryl, highly valued for its color and clarity.

Quartz (var. Amethyst)

Gemstone

Composition

SiO2 (Silicon dioxide)

Colors

Purple

Hardness

Varieties

None (Amethyst is the primary variety)

Amethyst is the purple variety of quartz, known for its calming properties.

Topaz

Gemstone

Composition

Al2SiO4(F,OH)2 (Aluminum silicate)

Colors

Yellow, various

Hardness

Varieties

Blue, Pink, White, etc.

Topaz is a gemstone known for its range of colors, commonly yellow.

Chalcedony (var. Agate)

Gemstone

Composition

SiO2 (Silicon dioxide)

Colors

Various

Hardness

Varieties

None (Agate is the primary variety)

Agate is a banded variety of chalcedony, often used for ornamental purposes.

Garnet

Gemstone

Composition

X3Y2(SiO4)3 (Silicate)

Colors

Red, green, yellow

Hardness

6.5-7.5

Varieties

Almandine, Pyrope, Spessartine, etc.

Opal

Gemstone

Composition

SiO2·nH2O (Hydrated silicon dioxide)

Colors

Various

Hardness

5.5-6.5

Varieties

Fire, Black, Boulder, Crystal, etc.

Lapis Lazuli

Rock

Composition

(Na,Ca)8(AlSiO4)6(SO4,S,Cl)1-2 (Silicate)

Colors

Blue, often with gold specks

Hardness

5-6

Varieties

None (Primary form is Lapis Lazuli)

Malachite

Mineral

Composition

Cu2CO3(OH)2 (Copper carbonate)

Colors

Green

Hardness

3.5-4

Varieties

None (Primary form is Malachite)

Pyrite

Mineral

Composition

FeS2 (Iron sulfide)

Colors

Metallic yellow

Hardness

6-6.5

Varieties

None (Primary form is Pyrite)

Fluorite

Mineral

Composition

CaF2 (Calcium fluoride)

Colors

Various

Hardness

Varieties

Purple, Blue, Green, Yellow, etc.

Jade

Gemstone

Composition

NaAlSi2O6 (Sodium aluminum silicate)

Colors

Green

Hardness

6-7

Varieties

Nephrite, Jadeite

Tourmaline

Gemstone

Composition

Boron silicate minerals

Colors

Various

Hardness

7-7.5

Varieties

Various

Tourmaline is a boron silicate mineral that occurs in a wide variety of colors and is popular in gemstones.

Gemstone

Composition

SiO2 (Silicon dioxide)

Colors

Green, often with sparkles

Hardness

Varieties

N/A

Aventurine is a variety of quartz with mica inclusions, giving it a sparkling appearance.

Celestite

Mineral

Composition

Strontium sulfate

Colors

Blue

Hardness

3-3.5

Varieties

N/A

Celestite is a blue mineral composed of strontium sulfate, often found in sedimentary rocks.

Quartz (var. Chalcedony)

Mineral

Composition

SiO2 (Silicon dioxide)

Colors

Various

Hardness

6.5-7

Varieties

Agate, Onyx, Jasper, etc.

Chalcedony (var. Chalcedony) is a cryptocrystalline variety of quartz with a wide range of varieties like Agate and Jasper.

Gemstone

Composition

SiO2 (Silicon dioxide)

Colors

Golden to red-brown

Hardness

5.5-6.5

Varieties

N/A

Tiger's Eye is a chatoyant gemstone known for its golden to red-brown color and fibrous texture.