AllMineralsRock
Gypsum Vs. Ulexite
Gypsum is a very popular mineral composed of calcium sulfate.[1] Ulexite is a popular mineral and its chemical composition is sodium calcium borate.[2]
Quick Facts on Differences of Gypsum and Ulexite
For a quick recap of the differences gypsum and ulexite:- While both gypsum and ulexite can be translucent or transparent, gypsum can be opaque.
- In terms of crystallography, gypsum is monoclinic while ulexite is triclinic.
- For chemical formulas, gypsum is CaSO4· 2H2O while ulexite is NaCaB5O9· 8H2O.
- While both gypsum and ulexite can be vitreous, in terms of luster, gypsum can be pearly and ulexite can be silky.
- Gypsum can be commonly brown, red or yellow while ulexite is often gray or white.
- Gypsum's specific gravity is higher than ulexite - gypsum ranges from 2.3 to 2.32 and ulexite ranges from 1.65 to 1.95.
Quick Facts on Similarities of Gypsum and Ulexite
The similarities of gypsum and ulexite include:- Gypsum and ulexite both streak white.
- Gypsum's rarity is similar to ulexite.
- Gypsum's hardness overlaps with ulexite - gypsum ranges from 1.5 to 2 and ulexite ranges from 1 to 2.5 on the Moh's scale.
Summary of Gypsum
Gypsum is a soft, white or gray mineral that belongs to the sulfate mineral family. It is composed of calcium sulfate dihydrate (CaSO4·2H2O) and is commonly found in sedimentary rocks. Gypsum is often found in thick beds or layers, and its crystals are usually flat and elongated. It has a hardness of 2 on the Mohs scale and a specific gravity of 2.3. One of the unique properties of gypsum is that it loses water when heated, which makes it an excellent material for making plaster.Summary of Ulexite
Ulexite is a mineral that is commonly known as TV rock or television stone due to its unique optical properties. It was first discovered in the mid-19th century in Boron, California, and has since been found in other locations around the world, including Turkey, Argentina, and Chile. Ulexite is a borate mineral that forms in evaporite deposits, typically in arid regions.Table Comparison of Gypsum vs Ulexite
| Gypsum (src) | Ulexite (src) | |
|---|---|---|
| Transparency | transparent, translucent, opaque | transparent, translucent |
| Chemical Formula | CaSO4· 2H2O | NaCaB5O9· 8H2O |
| Chemical Composition | calcium sulfate | sodium calcium borate |
| Specific Gravity | 2.3, 2.32, 2.33 | 1.65, 1.95 |
| Hardness | 1.5, 2 | 1, 2.5 |
| Streak | white | white |
| Crystallography | monoclinic | triclinic |
| Refractive Index | 1.52, 1.53 | 1.496, 1.519 |
| Hydrous | Yes | Yes |
| Colors | common: brown, red, yellow sometimes: blue, green, white, orange less common: tan, gray, pink, beige, black, colorless, band |
common: gray, white sometimes: colorless |
| Solubility | Soluble in dilute HCl | Slightly soluble in water |
| Category | sulfate | nesoborates |
| Birefringence | δ = 0.010 | δ = 0.028 |
| Fracture | uneven | splintery, uneven |