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Gowerite
3 in the gallery
Gowerite is a borate mineral with the chemical composition Ca[B5O8(OH)][B(OH)3]·3H2O. It forms monoclinic crystals that typically appear as acicular, prismatic, radiating, or fibrous aggregates with a vitreous to silky lustre. The colour range is colorless to white and it presents a white streak and a relatively low hardness of 3 on the Mohs scale, with a specific gravity near 2, making it a light, delicate specimen suitable for careful handling and display.
- Formula
- Ca[B5O8(OH)][B(OH)3]·3H2O
- Rarity
- Rare
- Stability
- Stable
- Collector interest
- Moderate Interest
- Classification notes
- Borates; Strunz 6.EC.10
Key characteristics
- Crystal system
- monoclinic
- Mohs hardness
- 3
- Specific gravity
- 2
- Luster
- vitreous, silky
- Transparency
- transparent, translucent
- Color
- colorless, white
- Streak
- white
- Crystal habit
- acicular, prismatic, radiating, fibrous
About Gowerite
Significant occurrences have been reported from the United States, where specimen collectors encounter Gowerite in borate-rich environments. Collectors value its distinctive fibrous and radiating habit, which can yield striking, thread-like crystal groups that are visually appealing under magnification. While not among the most common minerals, its rarity and unique borate chemistry give it a specialized appeal for cabinets focused on rare borates and monoclinic minerals. Collectors appreciate the mineral for its architectural crystal forms and the challenge of locating well-formed, lustrous specimens that reveal its intricate internal structure.
