Jade-Nephrite-Jadite Silicates-Inosilicates Group

Physical Features

1. Color- Green, white, gray, bluish, brown.

2. Streak- Colorless.

3. Luster- Greasy.

4. Cleavage-Good.

5. Transparency- Translucent.

6. Fracture- Splintery.

7. Hardness- 6.5-7.

8. Forms- Rare as a crystal

9. Crystal system-Monoclinic

Jade is actually two seperate minerals called Nephrite and Jadite. Nephrite (a member of the amphibole group), which consists of a microcrystaline interlocking fibrous matrix of calcium magnesium-iron rich amphibole. Jadite (a proxene) consists almost entirely of sodium and aluminium rich proxene with interlocking crystal matrix also. Both minerals form is of microcrystaline and generally occur in metamorphic rocks with a higher pressure, Low temperature, but are made up of different silicate minerals. Although Nephrite and Jadite are mainly recovered as pebbles and boulders it can also occure in the rocks which it was originally formed. Large occurrences can be found in Alaska, California, British Columbia, Japan and China.

Howlite Ca2B5Si09(OH)5 Silicates and Carbonates Group

Physical Featureshttp1. Color- White.

2. Streak- White.

3. Luster- Subvitreous.

4. Cleavage- None.

5. Transparency- Translucent to opaque.

6. Fracture- Conchoidal to uneven.

7. Hardness- 3.5.

8. Form-Nodular masses.

9. Crystal system-- Monoclinic.

In 1868 Canadian Chemist Henry Howe discovered the mineral Howlite, hence the name. Howlite is a calcium borosilicate hydroxide, which occurs in continental evaporite deposits. Many times Howlite is found with other borate and evaporite minerals, such as colemanite, ulexite, anhydrite, gypsum, and clays. Some say the Howlite imitates the mineral turquiose, especially when dyed. California and Canada hold the largest deposit's of Howlite, but can be found all over the world.