diff --git a/include/fastgltf/tools.hpp b/include/fastgltf/tools.hpp
index 8dce74243..82754589c 100644
--- a/include/fastgltf/tools.hpp
+++ b/include/fastgltf/tools.hpp
@@ -471,10 +471,10 @@ class IterableAccessor;
 template <typename ElementType, typename BufferDataAdapter = DefaultBufferDataAdapter>
 class AccessorIterator {
 protected:
-	const IterableAccessor<ElementType, BufferDataAdapter>* accessor;
-	std::size_t idx;
-	std::size_t sparseIdx = 0;
-	std::size_t nextSparseIndex = 0;
+	const IterableAccessor<ElementType, BufferDataAdapter>* accessor = nullptr;
+	std::size_t idx = std::numeric_limits<std::size_t>::max();
+	mutable std::size_t sparseIdx = 0;
+	mutable std::size_t nextSparseIndex = 0;
 
 public:
 	using value_type = ElementType;
@@ -486,6 +486,8 @@ class AccessorIterator {
 	// some things that these come with (e.g. std::distance using operator-).
 	using iterator_category = std::random_access_iterator_tag;
 
+	AccessorIterator() = default;
+
 	AccessorIterator(const IterableAccessor<ElementType, BufferDataAdapter>* accessor, std::size_t idx = 0)
 			: accessor(accessor), idx(idx) {
 		if (accessor->accessor.sparse.has_value()) {
@@ -512,7 +514,8 @@ class AccessorIterator {
 
 	[[nodiscard]] bool operator==(const AccessorIterator& iterator) const noexcept {
 		// We don't compare sparse properties
-		return idx == iterator.idx &&
+		return accessor == iterator.accessor &&
+			idx == iterator.idx &&
 			accessor->bufferBytes.data() == iterator.accessor->bufferBytes.data() &&
 			accessor->stride == iterator.accessor->stride &&
 			accessor->componentType == iterator.accessor->componentType;
@@ -522,7 +525,7 @@ class AccessorIterator {
 		return !(*this == iterator);
 	}
 
-	[[nodiscard]] ElementType operator*() noexcept {
+	[[nodiscard]] ElementType operator*() const noexcept {
 		if (accessor->accessor.sparse.has_value()) {
 			if (idx == nextSparseIndex) {
 				// Get the sparse value for this index
@@ -546,6 +549,10 @@ class AccessorIterator {
 	}
 };
 
+#if FASTGLTF_HAS_CONCEPTS
+static_assert(std::input_iterator<AccessorIterator<math::fvec4>>, "AccessorIterator needs to satisfy input_iterator");
+#endif
+
 template <typename ElementType, typename BufferDataAdapter = DefaultBufferDataAdapter>
 class IterableAccessor {
 	friend class AccessorIterator<ElementType, BufferDataAdapter>;
@@ -602,6 +609,10 @@ class IterableAccessor {
 	}
 };
 
+#if FASTGLTF_HAS_CONCEPTS
+static_assert(std::ranges::input_range<IterableAccessor<math::fvec4>>, "IterableAccessor needs to satisfy input_range");
+#endif
+
 FASTGLTF_EXPORT template <typename ElementType, typename BufferDataAdapter = DefaultBufferDataAdapter>
 #if FASTGLTF_HAS_CONCEPTS
 requires Element<ElementType>