What is a Keystone?

What is a keystone? You might think that all arches are made the same way. The fact is they are not all the same. Typical Roman arch with keystone. It is true that Egyptian, Babylonian, Greek and Assyrian civilizations used arches for underground structures such as drains and vaults. However, it was the Roman civilization (1000 B.C.E. - 500 C.E.) that first began using a keystone (also called a capstone) in their arches. The keystone is the topmost stone in the arch. The one in the illustration on the right is exaggerated in size from what a normal keystone would be.

Design for a Doorcase, Giuseppe Barberi, Italian, 1746–1809, Pen and brown ink, brush and brown wash on off-white laid paper, lined, Another variation of 1938-88-1693, with the emphasis on height. The overdoor

Keystone Species

PA Department of Labor & Industry on X: Having trouble creating your Keystone ID? Here are some tips that may help you troubleshoot issues you may be having. / X

PA Department of Labor & Industry on X: 🚨ATTN: We have received reports of user issues related to Keystone ID when logging into the new UC system We are actively working to

The keystone of our religion – Latter-dayBloke

What is a Keystone - Deepstash

Keystone species: Definition, origin, examples and importance – Eco-intelligent™

What is a Keystone?

The Capstone, the Cornerstone, and the Keystone are Three Different Types of Rock