Selenite
Selenite is one of the three forms of pure natural crystalline gypsum, with one other, satin spar having a very similar features, the other natural form is gypsum rock which is commonly crushed and used in the manufacture of plaster products.
In old English gypsum was referred to as spear stone (spærstn) because of its crystal spear-like projections, of which selenite and satin spar have the most notable. Selenite crystals are much rarer than satin spar crystals, whilst gypsum rock is relatively common. Other forms of crystalline gypsum are known as tabular gypsum, which is normally shorter blocks of satin spar, whilst desert roses, form with grains of sand and gypsum flower which are referred to as crystal habits.
Selenite crystals form in large flat, transparent crystals, often called plates or windows, whilst Satin Spar crystals are fibrous and white, often appear as raw rulers or wands which can be polished into palmstones or spheres. The naturally large flat transparent form of selenite crystals, might also be called Lapis Specularis a form of selenite that was put to good use by the Romans in the construction of specularia (sometimes referred to as specularium), which included the first types of windows before the development of glass for use in glazing, it was used to construct Roman winter gardens for horticulture.
[edit] Related articles on Designing Buildings
- Botanical gardens
- Construction materials.
- Conservatory.
- Drywall construction.
- Garden greenhouse.
- Gypsum.
- Hydroponics and buildings.
- Lime plaster.
- Minerals of local and national importance.
- Mortar.
- Permission for mining or working of minerals.
- Plaster.
- Specularium.
- The secret life of the Georgian garden.
- Types of glass.
- Winter gardens.
Featured articles and news
Twas the site before Christmas...
A rhyme for the industry and a thankyou to our supporters.
Plumbing and heating systems in schools
New apprentice pay rates coming into effect in the new year
Addressing the impact of recent national minimum wage changes.
EBSSA support for the new industry competence structure
The Engineering and Building Services Skills Authority, in working group 2.
Notes from BSRIA Sustainable Futures briefing
From carbon down to the all important customer: Redefining Retrofit for Net Zero Living.
Principal Designer: A New Opportunity for Architects
ACA launches a Principal Designer Register for architects.
A new government plan for housing and nature recovery
Exploring a new housing and infrastructure nature recovery framework.
Leveraging technology to enhance prospects for students
A case study on the significance of the Autodesk Revit certification.
Fundamental Review of Building Regulations Guidance
Announced during commons debate on the Grenfell Inquiry Phase 2 report.
CIAT responds to the updated National Planning Policy Framework
With key changes in the revised NPPF outlined.
Councils and communities highlighted for delivery of common-sense housing in planning overhaul
As government follows up with mandatory housing targets.
CIOB photographic competition final images revealed
Art of Building produces stunning images for another year.
HSE prosecutes company for putting workers at risk
Roofing company fined and its director sentenced.
Strategic restructure to transform industry competence
EBSSA becomes part of a new industry competence structure.
Major overhaul of planning committees proposed by government
Planning decisions set to be fast-tracked to tackle the housing crisis.
Industry Competence Steering Group restructure
ICSG transitions to the Industry Competence Committee (ICC) under the Building Safety Regulator (BSR).
Principal Contractor Competency Certification Scheme
CIOB PCCCS competence framework for Principal Contractors.
The CIAT Principal Designer register
Issues explained via a series of FAQs.