diff --git a/spec/index.html b/spec/index.html
index 004185e..706a965 100644
--- a/spec/index.html
+++ b/spec/index.html
@@ -588,9 +588,12 @@ <h3>IRIs</h3>
       is a <a>string</a> that conforms to the syntax
       defined in RFC 3987 [[!RFC3987]].</p>
 
-    <p>IRIs in the RDF abstract syntax MUST be <a data-cite="RFC3986#section-5">resolved</a>
-      per [[RFC3986]],
-      and MAY contain a fragment identifier.</p>
+    <p>An IRI in the RDF abstract syntax 
+      MUST be <a data-cite="RFC3986#section-5">resolved</a> per [[RFC3986]] and
+      MUST NOT be a <a data-cite="RFC3986#section-4.2">relative reference</a>.
+      An IRI MAY contain a <a data-cite="RFC3986#section-3.5">fragment identifier</a>.
+      An IRI SHOULD follow rules defined by the <a data-cite="RFC3986#section-3.1">IRI scheme</a>.
+    </p>
 
     <p><dfn>IRI equality</dfn>:
       Two IRIs are the same if and only if they consist of the same sequence of
@@ -644,6 +647,15 @@ <h3>IRIs</h3>
         if a <a data-cite="rfc3986#section-5.1">base IRI
         can be established</a> [[RFC3986]].</p>
 
+      <p><strong>URI Schemes:</strong>
+        Implementations are encouraged to enforce the scheme-specific rules of
+        the common schemes, such as the
+        <a data-cite="RFC7230#section-2.7.1">scheme rules for HTTP/HTTPS</a> and the
+        <a data-cite="did-core#identifier">DID syntax</a>.
+        Implementations ignore URI scheme rules
+        for schemes they do not recognize. 
+      </p>
+
       <p><strong>IRI normalization:</strong>
         Interoperability problems can be avoided by minting
         only IRIs that are normalized according to